Specifically substituted ladder type compounds for organic light emitting devices

ABSTRACT

Specifically substituted ladder type compounds of formula (I) wherein A is formula (II) a material for an organic electroluminescence device comprising at least one compound of formula (I), and an organic electroluminescence device which comprises one or more organic thin film layers including an emitting layer between a cathode and an anode, wherein at least one layer of the organic thin film layers comprises at least one compound of formula (I).

The present invention relates to specifically substituted ladder type compounds and organic electroluminescence devices comprising the same.

EP 2 301 926 A1 relates to a halogen compound, a polycyclic compound, and an organic electroluminescence device using the same, in particular, to an organic electroluminescence device, which shows high luminous efficiency and has a long lifetime, and to a polycyclic compound for realizing the same, and a halogen compound serving as an intermediate for the polycyclic compound. However, 9-substituted bis-carbazole derivatives are not mentioned.

EP 2 301 921 A1 relates to a polycyclic compound and an organic electroluminescence device using the polycyclic compound, in particular, an organic electroluminescence device, which shows high luminous efficiency and has a long lifetime. However, 9-substituted bis-carbazole derivatives are not mentioned.

WO 2011/137072 A1 relates to phosphorescent organic materials comprising a bicarbazole with a dibenzo or azadibenzo substitution. However, polycyclic compounds having at least five condensed rings comprising biscarbazoles are not mentioned.

Notwithstanding these developments, there remains a need for organic light emitting devices comprising new materials, especially host (=matrix) materials, charge transport materials, i.e. hole transport materials and electron transport materials, and/or charge/exciton blocker materials, i.e. electron/exciton blocker materials and hole/exciton blocker materials, to provide improved performance of electroluminescent devices.

Accordingly, it is an object of the present invention, with respect to the aforementioned prior art, to provide further materials suitable for use in organic electronic devices and further applications in organic electronics. More particularly, it should be possible to provide charge transport materials, i.e. hole transport materials and electron transport materials, and/or charge/exciton blocker materials, i.e. electron/exciton blocker materials and hole/exciton blocker materials, and host (=matrix) materials for use in organic electronic devices. The materials should be suitable especially for organic electronic devices which comprise at least one emitter, which is a phosphorescence emitter and/or a fluorescence emitter.

Furthermore, the materials should be suitable for providing organic electronic devices which ensure good performance of the organic electronic devices, especially good operative lifetimes and a low use and operating voltage of the organic electronic devices.

Said object is solved by a compound of formula (I)

wherein

A is

X_(A) and X_(B) each independently represent O or S;

r represents 1, 2 or 3; in the case that r is 2 or 3, X_(B) as well as Ar₃ are the same or different in each occurrence, preferably r is 1;

Ar₁, Ar₂ and Ar₃ each independently represent a substituted or unsubstituted aromatic hydrocarbon group having a ring structure formed of 6 to 30 carbon atoms or a substituted or unsubstituted heterocyclic group having a ring structure formed of 5 to 30 atoms, and which is linked to one aromatic hydrocarbon group of Ar₁, Ar₂ respectively Ar₃ via a carbon-carbon bond;

L represents a single bond, a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkylene group having a ring structure formed of 3 to 20 carbon atoms, a substituted divalent silyl group having 2 to 20 carbon atoms, a substituted or unsubstituted divalent aromatic hydrocarbon group having a ring structure formed of 6 to 30 carbon atoms or a substituted or unsubstituted divalent heterocyclic group having a ring structure formed of 5 to 30 atoms;

m is 1, 2 or 3; in the case that m is 2 or 3, L is the same or different in each occurrence, preferably m is 1;

R¹⁷ is a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms or a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms, an alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having a ring formed of 3 to 20 carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 24 carbon atoms;

L₁ is a single bond, a substituted or unsubstituted alkylene group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkylene group having a ring structure formed of 3 to 20 carbon atoms, a substituted divalent silyl group having 2 to 20 carbon atoms, a substituted or unsubstituted divalent aromatic hydrocarbon group having a ring structure formed of 6 to 30 carbon atoms, or a substituted or unsubstituted divalent heterocyclic group having a ring structure formed of 5 to 30 atoms;

n is 1, 2 or 3; in the case that n is 2 or 3, L₁ is the same or different in each occurrence;

Ar₄, Ar₅, Ar₆ and Ar₇ each independently represent a substituted or unsubstituted aromatic hydrocarbon group having a ring structure formed of 6 to 30 carbon atoms, or a substituted or unsubstituted heterocyclic group having a ring structure formed of 5 to 30 atoms;

wherein the dotted line is a bonding site.

The specific bis-carbazole substitution of the compounds according to formula (I) gives rise to materials, especially host, charge transport or charge blocking materials, that are highly suitable in organic electronic devices, preferably in organic electronic devices that emit green or red light. Moreover, a balanced charge transport, i.e. hole transport or electron transport, preferably hole transport and/or charge/exciton blocking, i.e. electron/exciton blocking or hole/exciton blocking, preferably electron/exciton blocking, in devices is achieved, especially resulting in low voltages or long lifetimes.

The compounds of the present invention may be used in organic electronic devices such as electrophotographic photoreceptors, photoelectric converters, organic solar cells (organic photovoltaics), switching elements, such as organic transistors, for example, organic FETs and organic TFTs, organic light emitting field effect transistors (OLEFETs), image sensors, dye lasers and organic electroluminescent devices, for example, organic light-emitting diodes (OLEDs).

Accordingly, a further subject of the present invention is directed to an organic electronic device, comprising a compound according to the present invention. The organic electronic device is preferably an electroluminescent device (EL device), such as an organic light-emitting diode (OLED).

The compounds of formula (I) can in principal be used in any layer of an EL device, but are preferably used as host, charge transport, i.e. hole transport or electron transport, and/or charge/exciton blocking, i.e. electron/exciton blocking or hole/exciton blocking, material. Particularly, the compounds of formula (I) are used as host material, preferably for green or red light emitting phosphorescence or fluorescence emitters, preferably phosphorescence emitters. In a further embodiment, the compounds of formula (I) are used as hole transport materials, preferably in devices comprising blue, green or red light emitting phosphorescence or fluorescence emitters, preferably fluorescence emitters.

Hence, a further subject of the present invention is directed to an emitting layer, comprising a compound of formula (I) according to the present invention. In said embodiment a compound of formula (I) is preferably used as host material or as co-host material together with one or more, preferably one, further host materials. More preferably, a combination of a compound of formula (I) as host material or as co-host material together with a phosphorescent emitter is used.

The terms aromatic hydrocarbon group having 6 to 30 ring carbon atoms, heterocyclic group having 5 to 30 ring atoms, alkyl group having 1 to 30 carbon atoms, alkenyl group having 2 to 30 carbon atoms, alkynyl group having 1 to 30 carbon atoms, cycloalkyl group having 3 to 25 carbon atoms, aralkyl group having 7 to 24 carbon atoms, alkylene group having 1 to 30 carbon atoms, cycloalkylene group having a ring structure formed of 3 to 20 carbon atoms, divalent silyl group having 2 to 20 carbon atoms, divalent aromatic hydrocarbon group having a ring structure formed of 6 to 30 carbon atoms, divalent heterocyclic group having a ring structure formed of 5 to 30 atoms, silyl group, halogen atom, alkoxy group having 1 to 25 carbon atoms, haloalkyl group having 1 to 20 carbon atoms, haloalkoxy group having 1 to 20 carbon atoms, aryloxy group having 6 to 30 ring carbon atoms, alkylthio group having 1 to 20 carbon atoms, arylthio group having 6 to 30 ring carbon atoms

are known in the art and generally have the following meaning, if said groups are not further specified in specific embodiments mentioned below:

The aromatic hydrocarbon group having 6 to 30 ring carbon atoms, preferably 6 to 24 ring carbon atoms, more preferably a substituted or unsubstituted aryl group having 6 to 24 carbon atoms, may be a non-condensed aromatic hydrocarbon group or a condensed aromatic hydrocarbon group. Specific examples thereof include phenyl group, naphthyl group, phenanthryl group, biphenyl group, terphenyl group, quaterphenyl group, fluoranthenyl group, triphenylenyl group, phenanthrenyl group, fluorenyl group, spirofluorenyl group, 9,9-diphenylfluorenyl group, 9,9′-spirobi[9H-fluorene]-2-yl group, 9,9-dimethylfluorenyl group, benzo[c]phenanthrenyl group, benzo[a]triphenylenyl group, naphtho[1,2-c]phenanthrenyl group, naphtho[1,2-a]triphenylenyl group, dibenzo[a,c]triphenylenyl group, and benzo[b]fluoranthenyl group, with phenyl group, naphthyl group, biphenyl group, terphenyl group, phenanthryl group, triphenylenyl group, fluorenyl group, spirobifluorenyl group, and fluoranthenyl group being preferred, and phenyl group, 1-naphthyl group, 2-naphthyl group, biphenyl-2-yl group, biphenyl-3-yl group, biphenyl-4-yl group, phenanthrene-9-yl group, phenanthrene-3-yl group, phenanthrene-2-yl group, triphenylene-2-yl group, 9,9-dimethylfluorene-2-yl group, fluoranthene-3-yl group being more preferred.

The heterocyclic group having 5 to 30 ring atoms, preferably 5 to 18 ring atoms, may be a non-condensed heterocyclic group or a condensed heterocyclic group. Specific examples thereof include the residues of pyrrole ring, isoindole ring, benzofuran ring, isobenzofuran ring, dibenzothiophene ring, isoquinoline ring, quinoxaline ring, phenanthridine ring, phenanthroline ring, pyridine ring, pyrazine ring, pyrimidine ring, pyridazine ring, triazine ring, indole ring, quinoline ring, acridine ring, pyrrolidine ring, dioxane ring, piperidine ring, morpholine ring, piperazine ring, carbazole ring, furan ring, thiophene ring, oxazole ring, oxadiazole ring, benzoxazole ring, thiazole ring, thiadiazole ring, benzothiazole ring, triazole ring, imidazole ring, benzimidazole ring, pyran ring, dibenzofuran ring, and benzo[c]dibenzofuran ring, and the residues of derivatives of these rings, with the residues of dibenzofuran ring, carbazole ring, dibenzothiophene ring, and derivatives of these rings being preferred, and the residues of dibenzofuran-2-yl group, dibenzofuran-4-yl group, 9-phenylcarbazole-3-yl group, 9-phenylcarbazole-2-yl group, dibenzothiophene-2-yl group, and dibenzothiophene-4-yl group being more preferred.

Examples of the alkyl group having 1 to 30 carbon atoms, preferably having 1 to 25 carbon atoms, include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, s-butyl group, isobutyl group, t-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group, n-octadecyl group, neopentyl group, 1-methylpentyl group, with methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, s-butyl group, isobutyl group, t-butyl group being preferred.

Examples of the alkenyl group having 1 to 30 carbon atoms, preferably having 1 to 25 carbon atoms, include ethenyl group, n-propenyl group, n-butenyl group, s-butenyl group, n-pentenyl group, n-hexenyl group, n-heptenyl group, n-octenyl group, n-nonenyl group, n-decenyl group, n-undecenyl group, n-dodecenyl group, n-tridecenyl group, n-tetradecenyl group, n-pentadecenyl group, n-hexadecenyl group, n-heptadecenyl group, n-octadecenyl group, neopentenyl group, 1-methylpentenyl group, with ethenyl group, n-propenyl group, n-butenyl group, s-butenyl group being preferred.

Examples of the alkynyl group having 1 to 30 carbon atoms, preferably having 1 to 25 carbon atoms, include ethynyl group, n-propynyl group, n-butynyl group, s-butynyl group, n-pentynyl group, n-hexynyl group, n-heptynyl group, n-octynyl group, n-nonynyl group, n-decynyl group, n-undecynyl group, n-dodecynyl group, n-tridecynyl group, n-tetradecynyl group, n-pentadecynyl group, n-hexadecynyl group, n-heptadecynyl group, n-octadecynyl group, neopentynyl group, 1-methylpentynyl group, with ethynyl group, n-propynyl group, n-butynyl group, s-butynyl group being preferred.

Examples of the cycloalkyl group having 3 to 25 carbon atoms, preferably having 3 to 20 carbon atoms include cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cyclooctyl group, and adamantyl group, with cyclopentyl group, and cyclohexyl group being preferred.

Examples of an aralkyl group having 7 to 24 carbon atoms, preferably 7 to 20 carbon atoms, include benzyl group, 2-phenylpropane-2-yl group, 1-phenylethyl group, 2-phenylethyl group, 1-phenylisopropyl group, 2-phenylisopropyl group, phenyl-t-butyl group, α-naphthylmethyl group, 1-α-naphthylethyl group, 2-α-naphthylethyl group, 1-α-naphthylisopropyl group, 2-α-naphthylisopropyl group, p-naphthylmethyl group, 1-β-naphthylethyl group, 2-β-naphthylethyl group, 1-β-naphthylisopropyl group, 2-β-naphthylisopropyl group, 1-pyrrolylmethyl group, 2-(1-pyrrolyl)ethyl group, p-methylbenzyl group, m-methylbenzyl group, o-methylbenzyl group, p-chlorobenzyl group, m-chlorobenzyl group, o-chlorobenzyl group, p-bromobenzyl group, m-bromobenzyl group, o-bromobenzyl group, p-iodobenzyl group, m-iodobenzyl group, o-iodobenzyl group, p-hydroxybenzyl group, m-hydroxybenzyl group, o-hydroxybenzyl group, p-aminobenzyl group, m-aminobenzyl group, o-aminobenzyl group, p-nitrobenzyl group, m-nitrobenzyl group, o-nitrobenzyl group, p-cyanobenzyl group, m-cyanobenzyl group, o-cyanobenzyl group, 1-hydroxy-2-phenyl isopropyl group, and 1-chloro-2-phenylisopropyl group.

Examples of the alkylene group (i.e. alkane-diyl group) having 1 to 30 carbon atoms include methylene group, ethylene group, n-propylene group, isopropylene group, n-butylene group, s-butylene group, isobutylene group, t-butylene group, n-pentylene group, n-hexylene group, n-heptylene group, n-octylene group, n-nonylene group, n-decylene group, n-undecylene group, n-dodecylene group, n-tridecylene group, n-tetradecylene group, n-pentadecylene group, n-hexadecylene group, n-heptadecylene group, n-octadecylene group, neopentylene group, 1-methylpentylene group, with methylene group, ethylene group, n-propylene group, isopropylene group, n-butylene group, s-butylene group, isobutylene group, t-butylene group being preferred.

Examples of the cycloalkylene group (i.e. cycloalkane-diyl group) having 3 to 20 carbon atoms include cyclopropylene group, cyclobutylene group, cyclopentylene group, cyclohexylene group, cyclooctylene group, and adamantylene group, with cyclopentylene group, and cyclohexylene group being preferred.

Examples of the divalent silyl group having 2 to 20 carbon atoms include divalent dimethylsilyl group, divalent diethylsilyl group, divalent dibutylsilyl group, divalent methylethylsilyl group, divalent t-butylmethylsilyl group, divalent vinylmethylsilyl group, divalent propylmethylsilyl group, divalent methylisopropylsilyl group, divalent methylpropylsilyl group, divalent methylbutylsilyl group, divalent methyltertiarybutylsilyl group, divalent ethylisopropylsilyl group, divalent phenylmethylsilyl group, divalent phenylmethylsilyl group, divalent phenyltertiarybutylsilyl group, and divalent diphenylsilyl group, with divalent dimethylsilyl group, divalent diethylsilyl group, divalent t-butylmethylsilyl group, divalent vinylmethylsilyl group, and divalent propylmethylsilyl group being preferred.

The divalent aromatic hydrocarbon group having 6 to 30 ring carbon atoms, preferably having 6 to 24 ring carbon atoms (arylene group having 6 to 24 carbon atoms) may be a non-condensed divalent aromatic hydrocarbon group or a condensed divalent aromatic hydrocarbon group.

Specific examples thereof include phenylene group, naphthylene group, phenanthrylene group, biphenyl-diyl group, terphenyl-diyl group, quaterphenyl-diyl group, fluoranthen-diyl group, triphenylenylene-diyl group, phenanthrene-diyl group, fluorene-diyl group, spirofluorene-diyl group, 9,9-diphenylfluorene-diyl group, 9,9′-spirobi[9H-fluorene]-2-diyl group, 9,9-dimethylfluorene-diyl group, benzo[c]phenanthrene-diyl group, benzo[a]triphenylene-diyl group, naphtho[1,2-c]phenanthrene-diyl group, naphtho[1,2-a]triphenylenylene-diyl group, dibenzo[a,c]triphenylenylene-diyl group, and benzo[b]fluoranthene-diyl group, with phenylene group, naphthylene group, biphenyl-diyl group, terphenyl-diyl group, phenanthryl-diyl group, triphenylenylen-diyl group, fluorene-diyl group, spirobifluorene-diyl group, and fluoranthene-diyl group being preferred, and 1,2-phenylene group, 1,3-phenylene group, 1,4-phenylene group, 1,4-naphthylene group, 1,8-naphthylene group, 2,6-naphthylene group, 2,7-naphthylene group, biphenyl-2,2′-diyl group, biphenyl-2,3′-diyl group, biphenyl-2,4′-diyl group, biphenyl-2,5′-diyl group, biphenyl-2,6′-diyl group, biphenyl-3,3′-diyl group, biphenyl-3,4′-diyl group, biphenyl-3,5′-diyl group, biphenyl-3,6′-diyl group, biphenyl-4,4′-diyl group, biphenyl-4,5′-diyl group, biphenyl-4,6′-diyl group, biphenyl-5,5′-diyl group, biphenyl-5,6′-diyl group, biphenyl-6,6′-diyl group, phenanthrene-9,10-diyl group, phenanthrene-2,3-diyl group, phenanthrene-2,7-diyl group, phenanthrene-2,8-diyl group, phenanthrene-2,6-diyl group, phenanthrene-2,9-diyl group, phenanthrene-2,10-diyl group, phenanthrene-3,9-diyl group, phenanthrene-3,10-diyl group, triphenylene-2,3-diyl group, triphenylene-2,5-diyl group, triphenylene-2,6-diyl group, triphenylene-2,7-diyl group, triphenylene-2,8-diyl group, 9,9-dimethylfluorene-2,7-diyl group, 9,9-dimethylfluorene-3,7-diyl group, 9,9-dimethylfluorene-1,4-diylgroup, fluoranthene-3,9-diyl group, fluoranthene-3,8-diyl group, fluoranthene-3,4-diyl group, fluoranthene-3,5-diyl group, fluoranthene-3,6-diyl group, fluoranthene-2,9-diyl group, fluoranthene-2,8-diyl group, fluoranthene-2,4-diyl group, fluoranthene-2,5-diyl group, fluoranthene-2,6-diyl group, fluoranthene-1,9-diylgroup, fluoranthene-1,8-diylgroup, fluoranthene-1,4-diylgroup, fluoranthene-1,5-diylgroup, fluoranthene-1,6-diylgroup being more preferred.

The divalent heterocyclic group having 5 to 30 ring atoms may be a non-condensed heterocyclic group or a condensed heterocyclic group. Specific examples thereof include the divalent residues of pyrrole ring, isoindole ring, benzofuran ring, isobenzofuran ring, dibenzothiophene ring, isoquinoline ring, quinoxaline ring, phenanthridine ring, phenanthroline ring, pyridine ring, pyrazine ring, pyrimidine ring, pyridazine ring, triazine ring, indole ring, quinoline ring, acridine ring, pyrrolidine ring, dioxane ring, piperidine ring, morpholine ring, piperazine ring, carbazole ring, furan ring, thiophene ring, oxazole ring, oxadiazole ring, benzoxazole ring, thiazole ring, thiadiazole ring, benzothiazole ring, triazole ring, imidazole ring, benzimidazole ring, pyran ring, dibenzofuran ring, and benzo[c]dibenzofuran ring, and the divalent residues of derivatives of these rings, with the divalent residues of dibenzofuran ring, carbazole ring, dibenzothiophene ring, and derivatives of these divalent rings being preferred, and the dibenzofuran-diyl group, 9-phenylcarbazole-diyl group and dibenzothiophene-diyl group being more preferred.

Examples of silyl groups (alkyl or aryl substituted silyl groups) include alkylsilyl groups having 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, including trimethylsilyl group, triethylsilyl group, tributylsilyl group, dimethylethylsilyl group, t-butyldimethylsilyl group, vinyldimethylsilyl group, propyldimethylsilyl group, dimethylisopropylsilyl group, dimethylpropylsilyl group, dimethylbutylsilyl group, dimethyltertiarybutylsilyl group, diethylisopropylsilyl group, and arylsilyl groups having 6 to 30 carbon atoms, preferably 6 to 18 carbon atoms, including phenyldimethylsilyl group, diphenylmethylsilyl group, diphenyltertiarybutylsilyl group, and triphenylsilyl group, with trimethylsilyl group, triethylsilyl group, t-butyldimethylsilyl group, vinyldimethylsilyl group, and propyldimethylsilyl group being preferred.

Examples of halogen atoms include fluorine, chlorine, bromine, and iodine, with fluorine being preferred.

Examples of an alkoxy group having 1 to 25 carbon atoms, preferably having 1 to 20 carbon atoms, include those having an alkyl portion selected from the alkyl groups mentioned above.

Examples of a haloalkyl group having 1 to 20 carbon atoms include the alkyl groups mentioned above wherein the hydrogen atoms thereof are partly or entirely substituted by halogen atoms.

Examples of a haloalkoxy group having 1 to 20 carbon atoms include the alkoxyl group mentioned above wherein the hydrogen atoms thereof are partly or entirely substituted by halogen atoms.

Examples of an aryloxy group having 6 to 30 ring carbon atoms, preferably having 6 to 24 carbon atoms include those having an aryl portion selected from the aromatic hydrocarbon groups mentioned above.

Examples of an alkylthio group having 1 to 25 carbon atoms, preferably having 1 to 20 carbon atoms include those having an alkyl portion selected from the alkyl groups mentioned above.

Examples of an arylthio group having 6 to 30 ring carbon atoms, preferably having 6 to 24 carbon atoms include those having an aryl portion selected from the aromatic hydrocarbon groups mentioned above.

Examples of an alkyl or aryl substituted carbonyl group (—(C=O)R* include those, wherein R* is an alkyl group having 1 to 30 carbon atoms or a aromatic hydrocarbon group having 6 to 30 ring carbon atoms, preferably R* is a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, s-butyl group, isobutyl group, t-butyl group, phenyl group, 1-naphthyl group or 2-naphthyl group.

Examples of a substituted phosphoryl group (—P(=O)(OR**)₂) include those, wherein R** is an alkyl group having 1 to 30 carbon atoms or a aromatic hydrocarbon group having 6 to 30 ring carbon atoms, preferably R** is a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, s-butyl group, isobutyl group, t-butyl group, phenyl group, 1-naphthyl group or 2-naphthyl group.

Examples of the optional substituent(s) indicated by “substituted or unsubstituted” and “may be substituted” referred to above or hereinafter include a halogen atom (fluorine, chlorine, bromine, iodine), a cyano group, an alkyl group having 1 to 30, preferably 1 to 6 carbon atoms, a cycloalkyl group having 3 to 20, preferably 5 to 12 carbon atoms, an alkoxyl group having 1 to 20, preferably 1 to 5 carbon atoms, a haloalkyl group having 1 to 20, preferably 1 to 5 carbon atoms, a haloalkoxyl group having 1 to 20, preferably 1 to 5 carbon atoms, a silyl group, an aromatic hydrocarbon group having 6 to 30 ring carbon atoms, preferably 6 to 18 ring carbon atoms, an aryloxy group having 6 to 30, preferably 6 to 18 ring carbon atoms, an aralkyl group having 7 to 24, preferably 7 to 20 carbon atoms, an alkylthio group having 1 to 20, preferably 1 to 5 carbon atoms, an arylthio group having 6 to 30, preferably 6 to 18 ring carbon atoms, and a heterocyclic group having 5 to 30 ring atoms, preferably 5 to 18 ring atoms.

The optional substituent is preferably a fluorine atom, a cyano group, an alkyl group having 1 to 30 carbon atoms, an aromatic hydrocarbon group having 6 to 30 ring carbon atoms, preferably 6 to 18 ring carbon atoms, and an heterocyclic group having 5 to 30 ring atoms, preferably 5 to 18 ring atoms; more preferably a fluorine atom, a phenyl group, a naphthyl group, a biphenyl group, a terphenyl group, a phenanthryl group, a triphenylenyl group, a fluorenyl group, a spirobifluorenyl group, a fluoranthenyl group, a residue based on a dibenzofuran ring, a residue based on a carbazole ring, a residue based on a dibenzothiophene ring, and their derivatives, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an s-butyl group, an isobutyl group, a t-butyl group, a cyclopentyl group, and a cyclohexyl group.

The optional substituent mentioned above may be further substituted by one or more of the optional substituents mentioned above.

The number of the optional substituents depends on the group which is substituted by said substituent(s). Preferred are 1, 2, 3 or 4 optional substituents, more preferred are 1, 2 or 3 optional substituents, most preferred are 1 or 2 optional substituents. In a further preferred embodiment, the groups mentioned above are unsubstituted.

The “carbon number of a to b” in the expression of “substituted or unsubstituted X group having a to b carbon atoms” is the carbon number of the unsubstituted X group and does not include the carbon atom(s) of an optional substituent.

The hydrogen atom referred to herein includes isotopes different from neutron numbers, i.e., light hydrogen (protium), heavy hydrogen (deuterium) and tritium.

The group of formula

In the Group of Formula

which is a part of formula (I),

X_(A) and X_(B) each independently represent O or S, preferably O;

r represents 1, 2 or 3; in the case that r is 2 or 3, X_(B) as well as Ar₃ are the same or different in each occurrence, preferably r is 1; and

Ar₁, Ar₂ and Ar₃ each independently represent a substituted or unsubstituted aromatic hydrocarbon group having a ring structure formed of 6 to 30 carbon atoms or a substituted or unsubstituted heterocyclic group having a ring structure formed of 5 to 30 atoms, and which is linked to one aromatic hydrocarbon group of Ar₁, Ar₂ respectively Ar₃ via a carbon-carbon bond; preferably, Ar₁, Ar₂ and Ar₃ each independently represent a substituted or unsubstituted aromatic hydrocarbon group having a ring structure formed of 6 to 10 carbon atoms or a substituted or unsubstituted aromatic heterocyclic group having a ring structure formed of 6 to 13 atoms;

more preferably, Ar₁, Ar₂ and Ar₃ each independently represent a substituted or unsubstituted aromatic hydrocarbon group having a ring structure formed of 6 to 10 carbon atoms.

Preferred suitable optional substituents of Ar₁, Ar₂ and Ar₃ are in each occurrence independently a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having a ring formed of 3 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 24 carbon atoms, a silyl group having 3 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having ring structure formed of 6 to 30 carbon atoms or a substituted or unsubstituted heterocyclic group having a ring structure formed of 5 to 30 atoms, or a substituted or unsubstituted alkylthio group having 1 to 20 carbon atoms, or a substituted or unsubstituted arylthio group having 6 to 30 carbon atoms, or a substituted or unsubstituted aryloxy group having 6 to 30 carbon atoms, a cyano group or a halogen atom; provided that, in the case of two adjacent substituents, said adjacent substituents may be bonded each other to form ring structures;

more preferred suitable optional substituents of Ar₁, Ar₂ and Ar₃ are in each occurrence independently a substituted or unsubstituted aromatic hydrocarbon group having ring structure formed of 6 to 30 carbon atoms or a substituted or unsubstituted heterocyclic group having a ring structure formed of 5 to 30 atoms;

most preferred suitable optional substituents of Ar₁, Ar₂ and Ar₃ are in each occurrence independently a substituted or unsubstituted aromatic hydrocarbon group having ring structure formed of 6 to 18 carbon atoms.

The total number of the optional substituents of Ar₁, Ar₂ and Ar₃ is preferably 1, 2, 3, 4 or 5, more preferably 1, 2 or 3, most preferably 1 or 2 and further most preferably 1.

Most preferred groups (I*) are therefore the following groups:

wherein

X²¹ to X³⁰ each independently represent CR_(X) or N, preferably CR_(X);

R_(x) is in each occurrence independently H, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having a ring formed of 3 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 24 carbon atoms, a silyl group having 3 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having ring structure formed of 6 to 30 carbon atoms or a substituted or unsubstituted heterocyclic group having a ring structure formed of 5 to 30 atoms, or a substituted or unsubstituted alkylthio group having 1 to 20 carbon atoms, or a substituted or unsubstituted arylthio group having 6 to 30 carbon atoms, or a substituted or unsubstituted aryloxy group having 6 to 30 carbon atoms, a cyano group or a halogen atom;

provided that, among X²¹ to X³⁰, if two or more atoms are CR_(X), any two of CR_(X)s may be bonded each other to form ring structures;

preferably, R_(x) is in each occurrence independently H, a substituted or unsubstituted aromatic hydrocarbon group having ring structure formed of 6 to 30 carbon atoms or a substituted or unsubstituted heterocyclic group having a ring structure formed of 5 to 30 atoms;

provided that, among X²¹ to X³⁰, if two or more atoms are CR_(X), any two of CR_(X)s may be bonded each other to form ring structures;

more preferably, R_(x) is in each occurrence independently H, a substituted or unsubstituted aromatic hydrocarbon group having ring structure formed of 6 to 18 carbon atoms;

provided that, among X²¹ to X³⁰, if two or more atoms are CR_(X), any two of CR_(X)s may be bonded each other to form ring structures;

wherein one of X²¹ to X³⁰ in each formula (I*a), (I*b), (I*c), (I*d) and (I*e) represents a bonding site to -(L)_(m)-A via a carbon atom.

Most preferred compounds are compounds (I*a), (I*b), (I*c) and (I*d), further most preferred are compounds (I*a), (I*b) and (I*c).

The Group -(L)_(m)-A

L represents a single bond, a substituted or unsubstituted alkylene group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkylene group having a ring structure formed of 3 to 20 carbon atoms, a divalent silyl group having 2 to 20 carbon atoms, a substituted or unsubstituted divalent aromatic hydrocarbon group having a ring structure formed of 6 to 30 carbon atoms or a substituted or unsubstituted divalent heterocyclic group having a ring structure formed of 5 to 30 atoms;

preferably, L represents a single bond, an alkylene group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkylene group having a ring formed of 3 to 20 carbon atoms, a divalent silyl group or a divalent silyl group having 2 to 20 carbon atoms, a substituted or unsubstituted, divalent aromatic hydrocarbon group having a ring structure formed of 6 to 24 carbon atoms, or a substituted or unsubstituted, divalent aromatic heterocyclic group having a ring structure formed of 5 to 24 atoms, which is linked with the group

through a carbon-carbon bond;

more preferably, L is a single bond, 1,3-diphenylene, 1,4-diphenylene, 1,2-diphenylene, biphenylene, divalent dibenzofuran, divalent dibenzothiophen, divalent substituted carbazole or divalent 9-phenylcarbazole;

most preferably, L is a single bond.

m is 1, 2 or 3; in the case that m is 2 or 3, L is the same or different in each occurrence, preferably m is 1.

A is

wherein the dotted line is a bonding site to L, and R¹⁷ is a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms or a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms, an alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having a ring formed of 3 to 20 carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 24 carbon atoms;

L₁ is a single bond, a substituted or unsubstituted alkylene group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkylene group having a ring structure formed of 3 to 20 carbon atoms, a substituted divalent silyl group having 2 to 20 carbon atoms, a substituted or unsubstituted divalent aromatic hydrocarbon group having a ring structure formed of 6 to 30 carbon atoms, or a substituted or unsubstituted divalent heterocyclic group having a ring structure formed of 5 to 30 atoms;

n is 1, 2 or 3; in the case that n is 2 or 3, L₁ is the same or different in each occurrence;

Ar₄, Ar₅, Ar₆ and Ar₇ each independently represent a substituted or unsubstituted aromatic hydrocarbon group having a ring structure formed of 6 to 30 carbon atoms, or a substituted or unsubstituted heterocyclic group having a ring structure formed of 5 to 30 atoms.

Suitable and preferred groups A are defined below.

The Group of Formula

The groups and indices Ar₁, Ar₂, Ar₃, X_(A), X_(B), r, L, m and A have been described above, and preferred groups A are additionally described below.

More preferred groups of formula (I) have one of the following formulae:

wherein the groups and indices X²¹ to X³⁰, X_(A), X_(B), L, m and A have been described above, and preferred groups A are additionally described below,

wherein one of X²⁷ to X³⁰ in each formula (Ia), (Ib), (Ic), (Id), (Ij) one of X²⁵ to X²⁶ in each formula (Ie), (If), (Ig), (Ih), (Ii) and one of X²¹ to X²⁴ in formula (Ib′) represents a bonding site to -(L)_(m)-A via a carbon atom.

Most preferred compounds are compounds (Ia), (Ib), (Ib′), (Ic), (Id), (Ig) and (If), further most preferred are compounds (Ia), (Ib), (Ib′) and (Ic).

Preferably, as mentioned above, X²¹ to X³⁰ each independently represent CR_(X). Most preferred compounds of formula (I) therefore have one of the following formulae:

wherein

X_(A), X_(B), L, m and A have been described above, and preferred groups A are additionally described below,

R²¹, R²², R²³, R²⁴, R²⁵, R²⁶, R²⁷, R²⁸, R²⁹ and R³⁰ are in each occurrence independently H, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having a ring formed of 3 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 24 carbon atoms, a silyl group having 3 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having ring structure formed of 6 to 30 carbon atoms or a substituted or unsubstituted heterocyclic group having a ring structure formed of 5 to 30 atoms, or a substituted or unsubstituted alkylthio group having 1 to 20 carbon atoms, or a substituted or unsubstituted arylthio group having 6 to 30 carbon atoms, or a substituted or unsubstituted aryloxy group having 6 to 30 carbon atoms, a cyano group or a halogen atom; provided that, two adjacent residues of the residues R²¹, R²², R²³, R²⁴, R²⁵, R²⁶, R²⁷, R²⁸, R²⁹ and R³⁰ may be bonded each other to form ring structures;

preferably, R²¹, R²², R²³, R²⁴, R²⁵, R²⁶, R²⁷, R²⁸, R²⁹ and R³⁰ are in each occurrence independently H, a substituted or unsubstituted aromatic hydrocarbon group having ring structure formed of 6 to 30 carbon atoms or a substituted or unsubstituted heterocyclic group having a ring structure formed of 5 to 30 atoms;

provided that, two adjacent residues of the residues R²¹, R²², R²³, R²⁴, R²⁵, R²⁶, R²⁷, R²⁸, R²⁹ and R³⁰ may be bonded each other to form ring structures;

more preferably, R²¹, R²², R²³, R²⁴, R²⁵, R²⁶, R²⁷, R²⁸, R²⁹ and R³⁰ are in each occurrence independently H, a substituted or unsubstituted aromatic hydrocarbon group having ring structure formed of 6 to 18 carbon atoms;

provided that, two adjacent residues of the residues R²¹, R²², R²³, R²⁴, R²⁵, R²⁶, R²⁷, R²⁸, R²⁹ and R³⁰ may be bonded each other to form ring structures;

wherein one of R²⁷ to R³⁰ in each formula (Ia-1), (Ib-1), (Ic-1), (Id-1), (Ij-1) one of R²⁵ to R²⁶ in each formula (Ie-1), (If-1), (Ig-1), (Ih-1), (Ii-1) and one of R²¹ to R²⁴ in formula (Ib′-1) represents a bonding to -(L)_(m)-A via a carbon atom.

Most preferred compounds are compounds (Ia-1), (Ib-1), (Ib′-1), (Ic-1), (Id-1), (Ig-1) and (If-1), further most preferred are compounds (Ia-1), (Ib-1) and (Ic-1).

Preferably, the bonding site to -(L)_(m)-A is at the position R²⁹ or R²⁷ in each formula (Ia-1), (Ib-1), (Ic-1), (Id-1), (Ij-1) R²⁵ or R²⁶ in each formula (Ie-1), (If-1), (Ig-1), (Ih-1), (Ii-1) and R²² or R²⁴ in formula (Ib′-1).

Further most preferred compounds of formula (I) are compounds (Ia-1), (Ib-1), (Ib′-1), (Ic-1), (Id-1), (Ig-1) and (If-1), wherein the bonding site to -(L)_(m)-A is at the position R²⁹ or R²⁷ in formula (Ia-1), (Ib-1), (Ic-1) and (Id-1), at the position R²⁵ or R²⁶ in formula (Ig-1) and (If-1) and at the position R²² or R²⁴ in formula (Ib′-1).

Even further most preferred are compounds (Ia-1), (Ib-1) and (Ic-1), wherein the bonding site to -(L)_(m)-A is at the position R²⁹ or R²⁷. Even further preferred are compounds (Ia-1), (Ib-1) and (Ic-1), wherein the bonding site to -(L)_(m)-A is at the position R²⁹.

The residues R²¹, R²², R²³, R²⁴, R²⁵, R²⁶, R²⁷, R²⁸, R²⁹ and R³⁰ which do not represent a bonding to -(L)_(m)-A are defined above. Preferably, 0, 1, 2 or 3, more preferably 0, 1 or 2, most preferably 0 or 1 and further most preferably 0 of the residues R²¹, R²², R²³, R²⁴, R²⁵, R²⁶, R²⁷, R²⁸, R²⁹ and R³⁰ which do not represent a bonding to -(L)_(m)-A are not H and the remaining residues R²¹, R^(22,) R²³, R²⁴, R²⁵, R²⁶, R²⁷, R²⁸, R²⁹ and R³⁰ which do not represent a bonding to -(L)_(m)-A are H.

Preferably, 0, 1, 2 or 3, more preferably 0, 1 or 2, most preferably 0 or 1 and further most preferably 0 of the residues R²¹, R²², R²³, R²⁴, R²⁵ and R²⁶ in each formula (Ia-1), (Ib-1), (Ic-1), (Id-1), (Ij-1) are not H; 0, 1, 2 or 3, more preferably 0, 1 or 2, most preferably 0 or 1 and further most preferably 0 of the residues R²¹, R²², R²³, R²⁴, R²⁷, R²⁸, R²⁹ and R³⁰ in each formula (Ie-1), (If-1), (Ig-1), (Ih-1), (Ii-1) are not H and 0, 1, 2 or 3, more preferably 0, 1 or 2, most preferably 0 or 1 and further most preferably 0 of the residues R²⁵, R²⁶, R²⁷, R²⁸, R²⁹ and R³⁰ in formula (Ib′-1) are not H. All other residues R²¹, R²², R²³, R²⁴, R²⁵, R²⁶, R²⁷, R²⁸, R²⁹ and R³⁰ in the compounds of formulae (Ia-1), (Ib-1), (Ic-1), (Id-1), (Ie-1), (If-1), (Ig-1), (Ih-1), (Ii-1), (Ij-1) and (Ib′-1) which do not represent a bonding to -(L)_(m)-A are preferably H.

In one preferred embodiment, all residues R², R²², R²³, R²⁴, R²⁵, R²⁶, R²⁷, R²⁸, R²⁹ and R³⁰ in the compounds of formulae (Ia-1), (Ib-1), (Ic-1), (Id-1), (Ie-1), (If-1), (Ig-1), (Ih-1), (Ii-1), (Ij-1) and (Ib′-1) which do not represent a bonding to -(L)_(m)-A are H.

Especially preferred compounds of formula (I) have one of the following formulae:

wherein

R²¹, R²², R²³, R²⁴, R²⁵, R²⁶, R²⁷, R²⁸, R²⁹ and R³⁰, X_(A), X_(B), m and A have been described above, and preferred groups A are additionally described below.

The Group of Formula A

A is

wherein the dotted line is a bonding site to L, and R¹⁷ is a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms or a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms, an alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having a ring formed of 3 to 20 carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 24 carbon atoms;

L₁ is a single bond, a substituted or unsubstituted alkylene group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkylene group having a ring structure formed of 3 to 20 carbon atoms, a substituted divalent silyl group having 2 to 20 carbon atoms, a substituted or unsubstituted divalent aromatic hydrocarbon group having a ring structure formed of 6 to 30 carbon atoms, or a substituted or unsubstituted divalent heterocyclic group having a ring structure formed of 5 to 30 atoms;

n is 1, 2 or 3; in the case that n is 2 or 3, L₁ is the same or different in each occurrence;

Ar₄, Ar₅, Ar₆ and Ar₇ each independently represent a substituted or unsubstituted aromatic hydrocarbon group having a ring structure formed of 6 to 30 carbon atoms, or a substituted or unsubstituted heterocyclic group having a ring structure formed of 5 to 30 atoms.

R¹⁷ is preferably a substituted or unsubstituted non-condensed aromatic hydrocarbon group or a substituted or unsubstituted condensed aromatic hydrocarbon group, for example including phenyl group, naphthyl group, phenanthryl group, biphenyl group, terphenyl group, quaterphenyl group, fluoranthenyl group, triphenylenyl group, phenanthrenyl group, fluorenyl group, spirofluorenyl group, 9,9-diphenylfluorenyl group, 9,9′-spirobi[9H-fluorene]-2-yl group, 9,9-dimethylfluorenyl group, benzo[c]phenanthrenyl group, benzo[a]triphenylenyl group, naphtho[1,2-c]phenanthrenyl group, naphtho[1,2-a]triphenylenyl group, dibenzo[a,c]triphenylenyl group, and benzo[b]fluoranthenyl group, with phenyl group, naphthyl group, biphenyl group, terphenyl group, phenanthryl group, triphenylenyl group, fluorenyl group, spirobifluorenyl group, and fluoranthenyl group being preferred, and phenyl group, 1-naphthyl group, 2-naphthyl group, biphenyl-2-yl group, biphenyl-3-yl group, biphenyl-4-yl group, phenanthrene-9-yl group, phenanthrene-3-yl group, phenanthrene-2-yl group, triphenylene-2-yl group, 9,9-dimethylfluorene-2-yl group, fluoranthene-3-yl group being more preferred, wherein the groups mentioned before are unsubstituted or substituted;

a substituted or unsubstituted non-condensed heterocyclic group or a substituted or unsubstituted condensed heterocyclic group, for example including the residues of pyrrole ring, isoindole ring, benzofuran ring, isobenzofuran ring, dibenzothiophene ring, isoquinoline ring, quinoxaline ring, phenanthridine ring, phenanthroline ring, pyridine ring, pyrazine ring, pyrimidine ring, pyridazine ring, triazine ring, indole ring, quinoline ring, acridine ring, pyrrolidine ring, dioxane ring, piperidine ring, morpholine ring, piperazine ring, carbazole ring, furan ring, thiophene ring, oxazole ring, oxadiazole ring, benzoxazole ring, thiazole ring, thiadiazole ring, benzothiazole ring, triazole ring, imidazole ring, benzimidazole ring, pyran ring, dibenzofuran ring, and benzo[c]dibenzofuran ring, and the residues of derivatives of these rings, with the residues of dibenzofuran ring, carbazole ring, dibenzothiophene ring, and derivatives of these rings being preferred, and the residues of dibenzofuran-2-yl group, dibenzofuran-4-yl group, 9-phenylcarbazole-3-yl group, 9-phenylcarbazole-2-yl group, dibenzothiophene-2-yl group, and dibenzothiophene-4-yl group being more preferred, wherein the groups mentioned before are unsubstituted or substituted;

methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, s-butyl group, isobutyl group, t-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group, n-octadecyl group, neopentyl group, 1-methylpentyl group, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cyclooctyl group, and adamantyl group, with methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, s-butyl group, isobutyl group, t-butyl group, cyclopentyl group, and cyclohexyl group being preferred, wherein the groups mentioned before are unsubstituted or substituted;

benzyl group, 2-phenylpropane-2-yl group, 1-phenylethyl group, 2-phenylethyl group, 1-phenylisopropyl group, 2-phenylisopropyl group, phenyl-t-butyl group, α-naphthylmethyl group, 1-α-naphthylethyl group, 2-α-naphthylethyl group, 1-α-naphthylisopropyl group, 2-α-naphthylisopropyl group, p-naphthylmethyl group, 1-β-naphthylethyl group, 2-β-naphthylethyl group, 1-β-naphthylisopropyl group, 2-β-naphthylisopropyl group, 1-pyrrolylmethyl group, 2-(1-pyrrolyl)ethyl group, p-methylbenzyl group, m-methylbenzyl group, o-methylbenzyl group, p-chlorobenzyl group, m-chlorobenzyl group, o-chlorobenzyl group, p-bromobenzyl group, m-bromobenzyl group, o-bromobenzyl group, p-iodobenzyl group, m-iodobenzyl group, o-iodobenzyl group, p-hydroxybenzyl group, m-hydroxybenzyl group, o-hydroxybenzyl group, p-aminobenzyl group, m-aminobenzyl group, o-aminobenzyl group, p-nitrobenzyl group, m-nitrobenzyl group, o-nitrobenzyl group, p-cyanobenzyl group, m-cyanobenzyl group, o-cyanobenzyl group, 1-hydroxy-2-phenyl isopropyl group, and 1-chloro-2-phenylisopropyl group, wherein the groups mentioned before are unsubstituted or substituted.

Suitable optional substituents and numbers of said optional substituents are mentioned above.

L₁ is preferably a single bond, an alkylene group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkylene group having a ring formed of 3 to 20 carbon atoms, a divalent silyl group or a divalent silyl group having 2 to 20 carbon atoms, a substituted or unsubstituted, divalent aromatic hydrocarbon group having a ring structure formed of 6 to 24 carbon atoms, or a substituted or unsubstituted, divalent aromatic heterocyclic group having a ring structure formed of 5 to 24 atoms, which is linked with the groups Ary and Ar₆ through a carbon-carbon bond;

more preferably, L₁ is a single bond, 1,3-diphenylene, 1,4-diphenylene, 1,2-diphenylene, biphenylene, divalent dibenzofuran, divalent dibenzothiophen, divalent substituted carbazole or divalent 9-phenylcarbazole;

most preferably, L₁ is a single bond.

Suitable optional substituents and numbers of said optional substituents are mentioned above.

n is 1, 2 or 3; in the case that n is 2 or 3, L₁ is the same or different in each occurrence. Preferably, n is 1 or 2, more preferably, n is 1.

Ar₄, Ar₅, Ar6 and Ar₇ each independently represent a substituted or unsubstituted aromatic hydrocarbon group having a ring structure formed of 6 to 30 carbon atoms, or a substituted or unsubstituted heterocyclic group having a ring structure formed of 5 to 30 atoms.

Preferred groups Ar₄

are

preferred group Ar₅

are

preferred groups Ar₆

are

and preferred groups Ar₇

are

wherein the dotted lines are bonding sites, and

X¹ to X⁸, and Y¹, to Y⁸ each independently represent CR_(Y) or N, preferably CR_(Y);

R_(Y) is in each occurrence independently H, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having a ring formed of 3 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 24 carbon atoms, a silyl group having 3 to 20 carbon atoms, a substituted or unsubstituted hydrocarbon group having ring structure formed of 6 to 30 carbon atoms or a substituted or unsubstituted aromatic heterocyclic group having a ring structure formed of 5 to 30 atoms, or a substituted or unsubstituted alkylthio group having 1 to 20 carbon atoms, or a substituted or unsubstituted arylthio group having 6 to 30 carbon atoms, or a substituted or unsubstituted aryloxy group having 6 to 30 carbon atoms, a cyano group or a halogen atom;

provided that, among X¹ to X⁸ and Y¹ to Y⁸, if two or more atoms are CR_(Y), any two of CR_(Y)s may be bonded each other to form ring structures

wherein one of X⁵, X⁶, X⁷ or X⁸ and one of Y¹, Y², Y³ or Y⁴, are bonded to each other via L₁.

Suitable optional substituents and numbers of said optional substituents are mentioned above.

Therefore, A is preferably a group of the following formula:

X¹ to X⁸, and Y¹, to Y⁸ each independently represent CR_(Y) or N, preferably CR_(Y);

R_(Y) is in each occurrence independently H, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having a ring formed of 3 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 24 carbon atoms, a silyl group having 3 to 20 carbon atoms, a substituted or unsubstituted hydrocarbon group having ring structure formed of 6 to 30 carbon atoms or a substituted or unsubstituted aromatic heterocyclic group having a ring structure formed of 5 to 30 atoms, or a substituted or unsubstituted alkylthio group having 1 to 20 carbon atoms, or a substituted or unsubstituted arylthio group having 6 to 30 carbon atoms, or a substituted or unsubstituted aryloxy group having 6 to 30 carbon atoms, a cyano group or a halogen atom;

provided that, among X¹, to X⁸ and Y¹ to Y⁸, if two or more atoms are CR_(Y), any two of CR_(Y)s may be bonded each other to form ring structures

wherein one of X⁵, X⁶, X⁷ or X⁸ and one of Y¹, Y², Y³ or Y⁴, are bonded to each other via L₁.

Preferably, R_(Y) is in each occurrence independently H, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having ring structure formed of 6 to 30 carbon atoms or a substituted or unsubstituted heterocyclic group having a ring structure formed of 5 to 30 atoms; provided that, among X^(,) to X⁸ and Y¹ to Y⁸, if two or more atoms are CR_(Y), any two of CRys may be bonded each other to form ring structures;

more preferably, R_(Y) is in each occurrence independently H, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, s-butyl group, isobutyl group, t-butyl group, a substituted or unsubstituted aromatic hydrocarbon group having ring structure formed of 6 to 18 carbon atoms, or a substituted or unsubstituted heterocyclic group having a ring structure formed of 5 to 18 atoms;

most preferably, R_(Y) is in each occurrence independently H, isopropyl group, n-butyl group, s-butyl group, isobutyl group, t-butyl group, substituted or unsubstituted phenyl, substituted or unsubstituted carbazolyl, substituted or unsubstituted dibenzofuryl, substituted or unsubstituted dibenzothienyl, further most preferably R_(Y) is in each occurrence H.

Suitable optional substituents and numbers of said optional substituents are mentioned above.

Preferably, in the group A, X¹, X², X³, X⁴, X⁵, X⁶, X⁷, X⁸, Y¹, Y², Y³, Y⁴, Y⁵, Y⁶, Y⁷ and Y⁸ is CR_(Y), wherein one of R_(Y) at one of the positions X⁵ to X⁸ and one of R_(Y) at the positions Y¹, to Y⁴ are replaced by the group -(L₁)_(n)-.

In the compounds of formula (I), the groups represented by formulae (a) and (b) are bonded to each other via -(L₁)_(n)- at one of X⁵ to X⁸ and one of Y¹ to Y⁴ (the dotted lines are bonding sites):

Specific examples of the bonding manner between formulae (a) and (b) via -(L₁)_(n)- are represented by X⁶-(L₁)_(n)-Y³, X⁶-(L₁)_(n)-Y², X⁶-(L₁)_(n)-Y⁴, X⁶-(L₁)_(n)-Y¹, X⁷-(L₁)_(n)-Y³, X⁵-(L₁)_(n)-Y³, X⁸-(L₁)_(n)-Y³, X⁷-(L₁)_(n)-Y², X⁷-(L₁)_(n)-Y⁴, X⁷-(L₁)_(n)-Y¹, X⁵-(L₁)_(n)-Y², X⁸-(L₁)_(n)-Y², X₈-(L₁)_(n)-Y⁴, X⁸-(L1)_(n)-Y¹, X⁵-(L₁)_(n)-Y¹, and X⁵-(L₁)_(n)-Y⁴. Preferably, X⁵, X⁶, X⁷ or X⁸ are bonded via -(L₁)_(n)- to Y² or Y³ or Y⁴, or Y², Y³ or Y⁴ are bonded via -(L₁)_(n)- to X⁶ or X. More preferably, the bonding manner is X⁶-(L₁)_(n)-Y³, X⁶-(L1)n-Y², X⁷-(L1)n-Y³ or X⁷-(L1)n-Y².

Preferably, group A is therefore selected from the group consisting of the following formulae:

More preferably, A is selected from the group consisting of the following formulae:

wherein X¹ to X⁸, Y¹, to Y⁸, R¹⁷, L₁ and n are defined above and the dotted line is a bonding site.

Most preferred groups A are selected from the group consisting of the following formulae:

wherein R¹⁷, L₁ and n are defined above and the dotted line is a bonding site, and

R^(1A), R^(2A), R^(3A), R^(4A), R^(5A), R^(6A), R^(7A), R^(8A), R^(1B), R^(2B), R^(3B), R^(4B), R^(5B), R^(6B), R^(7B), R^(8B) are defined as R_(Y), i.e. in each occurrence independently H, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having a ring formed of 3 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 24 carbon atoms, a silyl group having 3 to 20 carbon atoms, a substituted or unsubstituted hydrocarbon group having ring structure formed of 6 to 30 carbon atoms or a substituted or unsubstituted aromatic heterocyclic group having a ring structure formed of 5 to 30 atoms, or a substituted or unsubstituted alkylthio group having 1 to 20 carbon atoms, or a substituted or unsubstituted arylthio group having 6 to 30 carbon atoms, or a substituted or unsubstituted aryloxy group having 6 to 30 carbon atoms, a cyano group or a halogen atom;

provided that, among R^(1A) to R^(8A) and R^(1B) to R^(8B) any two adjacent residues may be bonded each other to form ring structures.

Preferably, R^(1A), R^(2A), R^(3A), R^(4A), R^(5A), R^(6A), R^(7A), R^(8A), R^(1B), R^(2B), R^(3B), R^(4B), R^(5B), R^(6B), R^(7B), R^(8B) are in each occurrence independently H, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having ring structure formed of 6 to 30 carbon atoms or a substituted or unsubstituted heterocyclic group having a ring structure formed of 5 to 30 atoms;

provided that, among R^(1A) to R^(8A) and R^(1B) to R^(8B) any two adjacent residues may be bonded each other to form ring structures;

more preferably, R^(1A), R^(2A), R^(3A), R^(4A), R^(5A), R^(6A), R^(7A), R^(8A), R^(1B), R^(2B), R^(3B), R^(4B), R^(5B), R^(6B), R^(7B), R^(8B) are in each occurrence independently H, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, s-butyl group, isobutyl group, t-butyl group, a substituted or unsubstituted aromatic hydrocarbon group having ring structure formed of 6 to 18 carbon atoms, or a substituted or unsubstituted heterocyclic group having a ring structure formed of 5 to 18 atoms; most preferably, R^(1A), R^(2A), R^(3A), R^(4A), R^(5A), R^(6A), R^(7A), R^(8A), R^(1B), R^(2B), R^(3B), R^(4B), R^(5B), R^(6B), R^(7B), R^(8B) are in each occurrence independently H, methyl, ethyl, n-propyl, isopropyl group, n-butyl group, s-butyl group, isobutyl group, t-butyl group, substituted or unsubstituted biphenyl, substituted or unsubstituted phenyl, substituted or unsubstituted carbazolyl, substituted or unsubstituted dibenzofuryl, substituted or unsubstituted dibenzothienyl, further most preferably R^(1A), R^(2A), R^(3A), R^(4A), R^(5A), R^(6A), R^(7A), R^(8A), R^(1B), R^(2B), R^(3B), R^(4B), R^(5B), R^(6B), R^(7B), R^(8B) are in each occurrence H.

Especially most preferred groups A are selected from the group consisting of the following formulae:

wherein R¹⁷, L₁ and n are defined above and the dotted line is a bonding site.

Particularly Preferred Compounds of Formula (I)

Particularly preferred compounds of formula (I) are the compounds of formulae (Ia-1a), (Ia-1 b), (Ib′-1 a), (Ib′-1 b), (Ic-1a), (Ic-1 b), (Id-1a), (Id-1 b), (If-1a), (If-1 b), (Ig-1 a) and (Ig-1b), wherein

R²¹, R²², R²³, R²⁴, R²⁵, R²⁶, R²⁷, R²⁸, R²⁹ and R³⁰, X_(A), X_(B), L and m have been described above, and A is (II′aa-1), (II′ab-1), (II′ac-1) or (II′ad-1), preferably, A is (II′aa-1a), (II′ab-1a), (II′ac-1a) or (II′ad-1a), wherein R¹⁷, L₁, n and R^(1A), R^(2A), R^(3A), R^(4A), R^(5A), R^(6A), R^(7A), R^(8A), R^(1B), R^(2B), R^(3B), R^(4B), R^(5B), R^(6B), R^(7B), R^(8B) are described above.

Most preferred compounds are the following compounds:

Synthesis of the Compounds of Formula (I)

The basic structures in formulae (I*a), (I*b), (I*c) and (I*d) are prepared as follows:

Basic Structure of Formula (I*a)

One example for the preparation of the basic structure of formula (I*a) is shown below:

Reaction for example in N-methyl-2-pyrrolidone in the presence of potassium carbonate.

Basic Structure of Formula (I*c)

One example for the preparation of the basic structure of formula (I*c) is shown below:

Reaction for example in N-methyl-2-pyrrolidone in the presence of potassium carbonate.

Basic Structure of Formula (I*d)

One example for the preparation of the basic structure of formula (I*d) is shown below:

Reaction for example in N-methyl-2-pyrrolidone in the presence of potassium carbonate.

Basic Structure of Formula (I*b)

One example for the preparation of the basic structure of formula (I*b) is shown below:

Reaction for example in N-methyl-2-pyrrolidone in the presence of potassium carbonate.

Basic Structure of Formula (rb)

One further example for the preparation of the basic structure of formula (I*b) is shown below: Step i)

Reaction for example in N-methyl-2-pyrrolidone in the presence of potassium carbonate.

Step ii)

Reaction for example in DMF in the presence of N-bromosuccinimide.

The functionalization of the basic structures A, B, C, D and E mentioned above with -(L)_(m)-A is for example carried out by reaction of the basic structures with

in the presence of a phosphine ligand (e.g. 2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl and Pd(0) (e.g. tris(dibenzylideneacetone)dipalladium(0)).

Details of the reaction steps and process conditions are mentioned above and in the examples of the present application.

Compounds of Formula (I) in Organic Electronics Applications

It has been found that the compounds of the formula (I) are particularly suitable for use in applications in which charge carrier conductivity is required, especially for use in organic electronics applications, for example selected from switching elements such as organic transistors, e.g. organic FETs and organic TFTs, organic solar cells and organic light-emitting diodes (OLEDs).

The term organic EL device (organic electroluminescence device) is used interchangeable with the term organic light-emitting diode (OLED) in the following; i.e. both terms have the same meaning in the sense of the present application.

The present invention further relates to a material for an organic EL device comprising at least one compound of formula (I).

The organic transistor generally includes a semiconductor layer formed from an organic layer with charge transport capacity; a gate electrode formed from a conductive layer; and an insulating layer introduced between the semiconductor layer and the conductive layer. A source electrode and a drain electrode are mounted on this arrangement in order thus to produce the transistor element. In addition, further layers known to those skilled in the art may be present in the organic transistor. The layers with charge transport capacity may comprise the compounds of formula (I).

The organic solar cell (photoelectric conversion element) generally comprises an organic layer present between two plate-type electrodes arranged in parallel. The organic layer may be configured on a comb-type electrode. There is no particular restriction regarding the site of the organic layer and there is no particular restriction regarding the material of the electrodes. When, however, plate-type electrodes arranged in parallel are used, at least one electrode is preferably formed from a transparent electrode, for example an ITO electrode or a fluorine-doped tin oxide electrode. The organic layer is formed from two sublayers, i.e. a layer with p-type semiconductor properties or hole transport capacity, and a layer formed with n-type semiconductor properties or charge transport capacity. In addition, it is possible for further layers known to those skilled in the art to be present in the organic solar cell. The layers with charge transport capacity may comprise the compounds of formula (I).

The compounds of formula (I) being particularly suitable in OLEDs for use as matrix material in a light-emitting layer and/or as charge and/or exciton blocker material, i.e. as electron/exciton blocker material or as hole/exciton blocker material, and/or charge transport material, i.e. hole transport material or electron transport material, preferably as matrix material in a light-emitting layer, especially in combination with a phosphorescence emitter and/or as hole transport material, especially in combination with a fluorescence emitter.

In the case of use of the inventive compounds of formula (I) in OLEDs, OLEDs which have good efficiencies and a long lifetime and which can be operated especially at a low use and operating voltage are obtained. The inventive compounds of formula (I) are suitable especially for use as matrix and/or charge transport, i.e. hole or electron transport, and/or charge blocker material, i.e. hole or electron blocker material. Furthermore, the compounds of the formula (I) can be used as conductor/complementary materials in organic electronics applications selected from switching elements and organic solar cells. (In the sense of the present application, the terms matrix and host are used interchangeable).

Organic EL Device (OLED)

The organic EL device as one embodiment of the invention comprises one or more organic thin film layers including an emitting layer between a cathode and an anode, and at least one layer of the organic thin film layers comprises the compound of formula (I).

As examples of the organic thin film layers that comprise the compound of formula (I), an anode-side organic thin film layer (hole-transporting layer, hole-injecting layer, or the like), an emitting layer, a cathode-side organic thin film layer (electron-transporting layer, electron-injecting layer, or the like) provided between a cathode and an emitting layer, a spacing layer, a barrier layer or the like can be given. The examples are not limited thereto.

The compound of formula (I) may be contained in any of the abovementioned layers, and can be used as a host material or a dopant material in the emitting layer of a fluorescent emitting unit, a host material in the emitting layer of a phosphorescent emitting unit, a hole-transporting layer, an electron-transporting layer or the like of an emitting unit.

Preferably, the compounds of the formula (I) are used as matrix materials (host materials), preferably in an emission layer of an OLED, more preferably in an emission layer of an OLED comprising at least one compound of the formula (I) and at least one emitter material, wherein the emitter material is preferably a fluorescent or phosphorescent emitter material, more preferably a green or red fluorescent or phosphorescent emitter material.

The organic EL device of the invention may be a fluorescent or phosphorescent monochromatic emitting device or may be a fluorescent/phosphorescent hybrid white emitting device. It may be a simple emitting device having a single emitting unit or a tandem emitting device having plural emitting units. Among them, the organic EL device may preferably be a phosphorescent emitting device.

As the representative device structure of a simple type organic EL device, the following device configuration can be given.

(1) Anode/Emitting Unit/Cathode

The emitting unit mentioned above may be a stacked type emitting unit comprising plural phosphorescent emitting layers or plural fluorescent emitting layers. In this case, in order to prevent diffusion of excitons generated in the phosphorescent emitting layer to the fluorescent emitting layer, a spacing layer may be provided between the emitting layers. The representative layer configuration of the emitting unit is given below.

(a) Hole-transporting layer/Emitting layer (/Electron-transporting layer)

(b) Hole-transporting layer/First phosphorescent emitting layer/Second phosphorescent emitting layer (/Electron-transporting layer)

(c) Hole-transporting layer/Phosphorescent emitting layer/Spacing layer/Fluorescent emitting layer (/Electron-transporting layer)

(d) Hole-transporting layer/First phosphorescent emitting layer/Second phosphorescent emitting layer/Spacing layer/Fluorescent emitting layer (/Electron-transporting layer)

(e) Hole-transporting layer/First phosphorescent emitting layer/Spacing layer/Second phosphorescent emitting layer/Spacing layer/Fluorescent emitting layer (/Electron-transporting layer)

(f) Hole-transporting layer/Phosphorescent emitting layer/Spacing layer/First fluorescent emitting layer/Second fluorescent emitting layer (/Electron-transporting layer)

(g) Hole-transporting layer/Electron barrier layer/Emitting layer (/Electron-transporting layer)

(h) Hole-transporting layer/Emitting layer/Hole barrier layer (/Electron-transporting layer)

(i) Hole-transporting layer/Fluorescent emitting layer/Triplet barrier layer (/Electron-transporting layer)

The phosphorescent or fluorescent emitting layer as mentioned above can emit different colors of light. Specifically, in the stacked emitting layer (d), a layer configuration of the hole transporting layer/first phosphorescent emitting layer (red emission)/second phosphorescent emitting layer (green emission)/spacing layer/fluorescent emitting layer (blue emission)/electron transporting layer or the like can be given.

Between each emitting layer and the hole-transporting layer or the spacing layer, an electron barrier layer may be provided appropriately. Between each emitting layer and the electron transporting layer, a hole-barrier layer may be provided appropriately. Due to provision of an electron-barrier layer or a hole-barrier layer, electrons or holes can be confined within the emitting layer, whereby possibility of recombination of carriers in the emitting layer can be increased, and the life can be improved.

As the represented device configuration of a tandem organic EL device, the following device configuration can be given.

(2) Anode/First Emitting Unit/Intermediate Layer/Second Emitting Unit/Cathode

Here, as the first emitting unit and the second emitting unit, the same emitting units as those mentioned above can independently be given, for example.

In general, the intermediate layer is called an intermediate electrode, an intermediate conductive layer, a carrier-generating layer, an electron-withdrawing layer, and a known material configuration that supplies electrons to the first emitting unit and supplies holes to the second emitting unit can be used.

FIG. 1 shows a schematic configuration of one example of the organic EL device of the invention. The organic EL device 1 comprises a substrate 2, an anode 3, a cathode 4 and an emitting unit 10 provided between the anode 3 and the cathode 4. The emitting unit 10 comprises an emitting layer 5 preferably comprising a host material and a dopant. A hole injecting and transporting layer 6 or the like may be provided between the emitting layer 5 and the anode 3 and an electron-injecting layer 8 and an electron transporting layer 7 or the like (electron injecting and transporting unit 11) may be provided between the emitting layer 5 and the cathode 4. An electron-barrier layer may be provided on the anode 3 side of the emitting layer 5 and a hole-barrier layer may be provided on the cathode 4 side of the emitting layer 5.

Due to such configuration, electrons or holes can be confined in the emitting layer 5, whereby possibility of generation of excitons in the emitting layer 5 can be improved.

Herein, a host that is combined with a fluorescent dopant is referred to as a fluorescent host and a host that is combined with a phosphorescent dopant is referred to as a phosphorescent host. The fluorescent host and the phosphorescent host are not distinguished only by the molecular structure thereof. That is, the phosphorescent host means a material constituting a phosphorescent emitting layer that contains a phosphorescent dopant and does not mean a material that cannot be used as a material constituting a fluorescent dopant. The same can be applied to a fluorescent host.

Substrate

The organic EL device is usually formed on a transparent substrate. The transparent substrate is a substrate for supporting the organic EL device, and is preferably a flat and smooth substrate having a 400-to-700-nm-visible-light transmittance of 50% or more. Specific examples thereof include glass plates and polymer plates. Examples of the glass plate include those obtained by using as raw materials soda-lime glass, barium/strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, quartz, or the like. Examples of the polymer plate include those obtained by using as raw materials polycarbonate, acrylic polymer, polyethylene terephthalate, polyethersulfide, polysulfone, or the like.

Anode

The anode of the organic EL device plays a role for injecting holes into its hole-transporting layer or emitting layer. It is effective to use one having a work function of 4.5 eV or more. As specific examples of the anode material, indium tin oxide alloy (ITO), tin oxide (N ESA), indium zinc oxide, gold, silver, platinum, copper, and the like can be given. The anode can be formed by forming these electrode materials into a thin film by vapor deposition, sputtering or the like. In the case where emission from the emitting layer is taken out through the anode, the transmittance of the anode to the emission is preferably more than 10%. The sheet resistance of the anode is preferably several hundred S2/0 or less. The film thickness of the anode, which varies depending upon the material thereof, is usually from 10 nm to 1 μm, preferably from 10 to 200 nm.

Cathode

The cathode plays a role for injecting electrons into its electron-injecting layer, electron-transporting layer or emitting layer. The cathode is preferably formed of a material having a small work function. The cathode material is not particularly restricted. As specific examples of the cathode material, indium, aluminum, magnesium, a magnesium-indium alloy, a magnesium-aluminum alloy, an aluminum-lithium alloy, an aluminum-scandium-lithium alloy, a magnesium-silver alloy or the like can be given. As in the case of the anode, the cathode can be formed by forming the materials into a thin film by a deposition method, a sputtering method or the like. If necessary, emission can be outcoupled from the cathode side.

Emitting Layer

The present invention relates—in one embodiment—to an organic electroluminescence device, wherein the light emitting layer comprises at least one compound of formula (I).

The emitting layer is an organic layer having an emitting function, and where a doping system is used, it usually comprises a host material and a dopant material.

The host material has a function of accelerating recombination of electrons and holes and confining excitons within the emitting layer. The dopant material has a function of emitting efficiently excitons obtained by recombination.

In the case of a phosphorescent device, the host material has a function of confining excitons mainly generated by a dopant within the emitting layer.

Here, in the emitting layer, a double host (also referred to as a host/cohost) that adjusts the carrier balance in the emitting layer may be used by combining an electron-transporting host and a hole-transporting host or by other methods. It is preferred that the emitting layer comprise a first host material and a second host material and that at least one component of the first host material and the second host material is the compounds of the formula (I) according to the invention.

Double dopant may be used in which two or more types of dopant materials having a high quantum yield are incorporated, and each dopant emits light. Specifically, by allowing a host, a red dopant and a green dopant to be co-deposited, yellow emission from the common emitting layer, whereby yellow emission is realized.

As for the emitting layer, by allowing plural emitting layers to be a stacked body, electrons and holes are accumulated in the interface of the emitting layers, whereby the recombination region is concentrated in the interface of the emitting layers. As a result, the quantum efficiency is improved.

Easiness in injection of holes to the emitting layer and easiness in injection of electrons to the emitting layer may differ. Further, the hole-transporting performance and the electron transporting performance indicated by the mobility of holes and electrons in the emitting layer may differ from each other.

The emitting layer can be formed by a known method such as a deposition method, a spin coating method, a LB method (Langmuir Blodgett method) or the like, for example. The emitting layer can also be formed by forming a solution obtained by dissolving a binder such as a resin and material compounds in a solvent into a thin film by a spin coating method and the like. The emitting layer is preferably a molecular deposited film. The “molecular deposited film” means a thin film formed by deposition of a raw material compound in a vapor phase or a film formed by solidification of a raw material compound in a solution state or a liquid phase state. Normally, this molecular deposited film differs from a thin film (molecular accumulated film) formed by a LB method in aggregation structure or high-order structure, or differ in function derived from such difference in structure.

In a more preferred embodiment, the light-emitting layer is formed from 0.1 to 70% by weight, preferably 1 to 30% by weight, of at least one of the emitter materials and 30 to 99.9% by weight, preferably 70 to 99% by weight, of at least one of the matrix materials mentioned in the specification—in one embodiment at least one compound of the formula (I)—where the sum total of the emitter material and of the matrix material adds up to 100% by weight.

(1) Phosphorescent Emitting Layer

The phosphorescent emitting layer usually comprises at least one emitter material and at least one host material. The phosphorescent host is a compound which confines the triplet energy of the phosphorescent dopant efficiently in the light emitting layer to cause the phosphorescent dopant to emit light efficiently.

A host material for phosphorescent emitting layer is usually selected from known phosphorescent host materials. Specific examples of the preferable phosphorescent host are, nitrogen-containing heteroaromatics, such as, indole derivatives, carbazole derivatives, pyridine derivatives, pyrimidine derivatives, triazine derivatives, quinoline derivatives, isoquinoline derivatives, quinazoline derivatives, nitrogenated-dibenzothiophene derivatives, nitrogenated-dibenzofuran derivatives, imidazole derivatives, such as benzimidazole derivatives, imidazopyridine derivatives, Benzimidazophenanthridine derivatives, benzimidzobenzimidazole derivatives; oxygen or sulfur containing heteroaromatics, such as thiophene derivatives, furan derivatives, benzothiophene derivatives, benzofuran derivatives, dibenzothiophene derivatives, dibenzofuran derivatives; aryl or heteroaryl substituted amine derivatives; metal complexes; aromatic hydrocarbon derivatives, such as benzene derivatives naphthalene derivatives, phenanthrene derivatives, triphenylene derivatives, fluorene derivatives, and so on, preferably, nitrogen containing heteroaromatics, the most preferably, the compounds of the formula (I).

According to one embodiment, the light-emitting layer comprises at least one emitter material and at least two matrix materials, wherein one of the matrix materials is a compound of the formula (I) and the other matrix material(s) is/are used as co-host(s). Suitable other host materials than the compounds of formula (I) (co-hosts) are mentioned below. However, it is also possible to use two or more different compounds of formula (I) as host material in the light-emitting layer in an OLED of the present application.

Said second host material is selected from general phosphorescent host materials. Specific examples are selected from above mentioned derivatives, preferably, nitrogen containing heteroaromatics, more preferably, following general formula (N-1). The present invention therefore further relates to an organic electroluminescence device, wherein the light emitting layer comprises a heterocyclic derivative represented by the general formula (N-1) and preferably at least one compound of formula (I).

X^(n1), to X^(n3) each independently represents CR^(n4) or N,

R^(n1) to R^(n4) each independently represents hydrogen, halogen atom, a substituted or unsubstituted alkyl group having 1 to 25 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 25 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 25 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 25 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 25 carbon atoms, a substituted or unsubstituted aryl group having 6 to 24 carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 30 cyclic atoms, a substituted or unsubstituted aryloxy group having 6 to 24 carbon atoms, a substituted or unsubstituted alkylthio group having 1 to 25 carbon atoms, a substituted or unsubsituted arylthio group having 6 to 24 carbon atoms, alkyl or aryl substituted silyl group, alkyl or aryl substituted carbonyl group, or a substituted phosphoryl group,

in the case of at least one of X^(n1) to X^(n3) represent CR^(n4), two or more substituents selected among R^(n1)˜R^(n4) may be bonded to each other to form a ring structure.

In one embodiment of the present invention, the compound of formula (N-1) is preferably represented by the formula (N-21).

Wherein,

each of X^(n1) to X^(n3), R^(n5) and R^(n6) is as defined in formula (N-1),

L^(n1) represents a substituted or unsubstituted aryl group having 6 to 24 carbon atoms, or a substituted or unsubstituted heterocyclic group having 5 to 30 cyclic atoms,

nf is 0, 1, 2, 3 or 4, when f is 2, 3 or 4, the plural L^(n1)s may be same or different each other,

Y^(n1) is carbon atom or nitrogen atom,

Ar^(n1) represents a substituted or unsubstituted aryl group having 6 to 24 carbon atoms which shares a carbon atom of an adjacent nitrogen-containing 5-membered ring and Y1¹¹ and is fused to the nitrogen-containing 5-membered ring, or a substituted or unsubstituted heterocyclic group having 5 to 30 cyclic atoms which shares a carbon atom of an adjacent nitrogen-containing 5-membered ring and Y1¹¹ and is fused to the nitrogen-containing 5-membered ring,

R^(n50) and R^(n51) each independently represents hydrogen, halogen atom, a substituted or unsubstituted alkyl group having 1 to 25 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 25 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 25 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 25 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 25 carbon atoms, a substituted or unsubstituted aryl group having 6 to 24 carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 30 cyclic atoms, a substituted or unsubstituted aryloxy group having 6 to 24 carbon atoms, a substituted or unsubstituted alkylthio group having 1 to 25 carbon atoms, a substituted or unsubsituted arylthio group having 6 to 24 carbon atoms, alkyl or aryl substituted silyl group, alkyl or aryl substituted carbonyl group, a substituted phosphoryl group or a cyano group, or R⁵⁰ and R⁵¹ may be bonded to each other to form a substituted or unsubstituted aryl group having 6 to 24 carbon atoms.

The compound represented by formula (N-21) is preferably represented by formula (N-22).

Wherein

X^(n1) to X^(n3), R^(n5), R^(n6), L^(n1), nf, Y^(n1) and Ar^(n1) are as defined in formula (N-21),

R^(n52) represents hydrogen, halogen atom, a substituted or unsubstituted alkyl group having 1 to 25 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 25 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 25 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 25 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 25 carbon atoms, a substituted or unsubstituted aryl group having 6 to 24 carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 30 cyclic atoms, a substituted or unsubstituted aryloxy group having 6 to 24 carbon atoms, a substituted or unsubstituted alkylthio group having 1 to 25 carbon atoms, a substituted or unsubsituted arylthio group having 6 to 24 carbon atoms, alkyl or aryl substituted silyl group, alkyl or aryl substituted carbonyl group, a substituted phosphoryl group or a cyano group,

nc is 0, 1, 2, 3 or 4, when c is 2, 3 or 4, the plural R^(n52)s may be same or different each other and adjacent R^(n52)s may be bonded to each other to form a ring structure.

The compound represented by formula (N-22) is preferably represented by formula (N-23).

Wherein X^(n1), to X^(n3), R^(n5), R^(n6), L^(n1), nf, R^(n52) and nc are as defined in formula (N-22).

The compound represented by formula (N-23) is preferably represented by formula (N-24).

Wherein X^(n,) to X^(n3), R^(n5), R^(n6), L^(n1), nf, R^(n52) and nc are as defined in formula (N-23),

nd is 0, 1, 2 or 3, when nd is 2 or 3, the plural R^(n52) are same or different each other,

R^(n53) represents a substituted or unsubstituted alkyl group having 1 to 25 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 25 carbon atoms, a substituted or unsubstituted aryl group having 6 to 24 carbon atoms or a substituted or unsubstituted heterocyclic group having 5 to 30 cyclic atoms.

In another embodiment, the compound represented by formula (N-22) is preferably represented by formula (N-25).

Wherein X^(n1) to X^(n3), R^(n5), R^(n6), L^(n1), nf, R^(n52) and nc are as defined in formula (N-22),

Y^(n2) represents CR^(n54)R^(n55), NR^(n55), oxygen atom or sulfur atom,

R^(n54), R^(n55) and R^(n56) each independently represents a substituted or unsubstituted alkyl group having 1 to 25 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 25 carbon atoms, a substituted or unsubstituted aryl group having 6 to 24 carbon atoms or a substituted or unsubstituted heterocyclic group having 5 to 30 cyclic atoms,

Ar^(n2) represents a substituted or unsubstituted aryl group having 6 to 24 carbon atoms which shares carbon atoms of two adjacent nitrogen-containing 5-membered rings and is fused to the two nitrogen-containing 5-membered rings, or a substituted or unsubstituted heterocyclic group having 5 to 30 cyclic atoms which shares carbon atoms of two adjacent nitrogen-containing 5-membered rings and is fused to the two nitrogen-containing 5-membered rings.

Y^(n2) in formula (N-25) preferably represents CR^(n54)R^(n55) or NR^(n56) (R^(n54) to R^(n56) are as defined in formula (N-25)).

The compound represented by formula (N-25) is preferably represented by any one of the following formulae (N-26A) to (N-26F).

Wherein X^(n1) to X^(n3), R^(n5), R^(n6), L^(n1), nf, R^(n52) and nc are as defined in formula (N-25), R^(n57) represents a substituted or unsubstituted alkyl group having 1 to 25 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 25 carbon atoms, a substituted or unsubstituted aryl group having 6 to 24 carbon atoms or a substituted or unsubstituted heterocyclic group having 5 to 30 cyclic atoms,

e is 0, 1 or 2, when e is 2, the plural R^(n52)s may be same or different each other.

The compound represented by formula (N-25) is more preferably represented by any one of the following formulae (N-27A) to (N-27F).

Wherein X^(n1) to X^(n3), R^(n5), R^(n6), L^(n1), nf, R^(n52) and nc are as defined in formula (N-25), R^(n58) represents a substituted or unsubstituted alkyl group having 1 to 25 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 25 carbon atoms, a substituted or unsubstituted aryl group having 6 to 24 carbon atoms or a substituted or unsubstituted heterocyclic group having 5 to 30 cyclic atoms,

ne is 0, 1 or 2, when ne is 2, the plural R^(n52)s may be same or different each other.

In another embodiment, the compound represented by formula (N-22) can be represented by formula (N-28).

Wherein X^(n1), to X^(n3), R^(n5), R^(n8), L^(n1), nf, R^(n52) and nc are as defined in formula (N-22).

In another embodiment, the compound represented by formula (N-1) is preferably represented by formula (N-30).

Wherein X^(n1) to X^(n3), R^(n5) and R^(n6) are as defined in formula (N-1),

L1 represents a substituted or unsubstituted arylene group having 6 to 24 carbon atoms or a substituted or unsubstituted heteroarylene group having 5 to 30 cyclic atoms,

nf is 0, 1, 2, 3 or 4, when nf is 2, 3 or 4, the plural L^(n1)s may be same or different each other,

R^(n60) represents a substituted or unsubstituted fused-aryl group having 10 to 24 carbon atoms or a substituted or unsubstituted fused-heteroaryl group having 9 to 30 cyclic atoms.

Said substituted or unsubstituted fused-aryl group having 10 to 24 carbon atoms of R^(n60) is preferably a mono-valent residue of the compound represented by formula (a1-1) or (a1-2).

Wherein R^(n21) to R^(n36) each independently represents hydrogen atom or substituent R^(b), when plural R^(b)s exist, the plural R^(b)s may be same or different each other, and the plural R^(b)s may be bonded to each other to form a ring structure,

R^(b) represents hydrogen, a substituted or unsubstituted alkyl group having 1 to 25 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 25 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 25 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 25 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 25 carbon atoms, a substituted or unsubstituted aryl group having 6 to 24 carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 30 cyclic atoms, a substituted or unsubstituted aryloxy group having 6 to 24 carbon atoms, a substituted or unsubstituted alkylthio group having 1 to 25 carbon atoms, a substituted or unsubsituted arylthio group having 6 to 24 carbon atoms, alkyl or aryl substituted silyl group, alkyl or aryl substituted carbonyl group, a substituted phosphoryl group or a cyano group.

Preferable examples of the compound represented by formula (a1-1) are as follows.

Among the above examples, a fused-aryl ring containing 4 or more rings, such as triphenylenyl group, is preferable.

Preferable examples of the compound represented by formula (a1-2) are as follows.

Among the above examples, a fused-aryl ring containing 4 or more rings, such as fluoranthenyl group is preferable.

As the fused-heteroaryl group having 9 to 30 cyclic atoms of R^(n60), a fused-heteroaryl group having 9 to 30 cyclic atoms selected from the above-mentioned heteroaryl groups can be used. The substituted or unsubstituted fused-heteroaryl group having 9 to 30 cyclic atoms of R^(n60) is preferably a mono-valent residue of the compound represented by formula (a2).

Wherein X^(n51) to X^(n58) each independently represents CH, C(Rb) or N,

R^(b) represents a substituted or unsubstituted alkyl group having 1 to 25 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 25 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 25 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 25 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 25 carbon atoms, a substituted or unsubstituted aryl group having 6 to 24 carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 30 cyclic atoms, a substituted or unsubstituted aryloxy group having 6 to 24 carbon atoms, a substituted or unsubstituted alkylthio group having 1 to 25 carbon atoms, a substituted or unsubsituted arylthio group having 6 to 24 carbon atoms, alkyl or aryl substituted silyl group, alkyl or aryl substituted carbonyl group, a substituted phosphoryl group or a cyano group,

when plural R^(b)s exist, the plural R^(b)s may be same or different each other, and the plural R^(b)s may be bonded to each other to form a ring structure,

Y^(n4) represents oxygen atom, sulfur atom, —NR^(d)— or —C(R^(e))(R^(f))—,

R^(d), R^(e) and R^(f) each independently represents hydrogen atom or substituent R^(b), when both of R^(e) and R^(f) are R^(b), the R^(b)s may be bonded to each other to form a ring structure.

The mono-valent residue of the compound represented by formula (a2) is preferably mono-valent residue of the compound represented by formula (a2-1).

Wherein Y^(n4) is as defined in formula (a2),

R^(n71) to R^(n78) each independently represents hydrogen atom or substituent R^(b),

R^(b) is as defined in formula (a2),

when plural R^(b)s exist, the plural R^(b)s may be same or different and may be bonded to each other to form a ring structure.

The compound represented by formula (N-30) is preferably represented by formula (N-31).

Wherein X^(n1) to X^(n3), R^(n5), R^(n6), Ln1 and nf are as defined in formula (N-30),

R^(n59) represents a substituted or unsubstituted alkyl group having 1 to 25 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 25 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 25 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 25 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 25 carbon atoms, a substituted or unsubstituted aryl group having 6 to 24 carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 30 cyclic atoms, a substituted or unsubstituted aryloxy group having 6 to 24 carbon atoms, a substituted or unsubstituted alkylthio group having 1 to 25 carbon atoms, a substituted or unsubsituted arylthio group having 6 to 24 carbon atoms, alkyl or aryl substituted silyl group, alkyl or aryl substituted carbonyl group, a substituted phosphoryl group or a cyano group,

nc is 0, 1, 2, 3 or 4, nd is 0, 1, 2 or 3,

when nc is 2, 3 or 4, and/or when nd is 2 or 3, the plural R^(n59)s may be same or different, and the plural R^(n59)s may be bonded to each other to form a ring structure.

In another embodiment, the compound represented by formula (N-30) is preferably represented by formula (N-32).

Wherein X^(n1), to X^(n3), R^(n5), R^(n6), L^(n1) and nf are as defined in formula (N-30),

R^(n61) represents a substituted or unsubstituted fused-heteroaryl group having 9 to 30 cyclic atoms and not containing nitrogen atom.

As the fused-heteroaryl group having 9 to 30 cyclic atoms and not containing nitrogen atom of R^(n61), a fused-heteroaryl group having 9 to 30 cyclic atoms and not containing nitrogen atom selected from the above-mentioned heteroaryl groups can be used.

The compound represented by formula (N-32) is preferably represented by formula (N-33).

Wherein X^(n1) to X^(n3), R^(n5), R^(n6), Ln1 and nf are as defined in formula (N-32),

R^(n62) represents a substituted or unsubstituted alkyl group having 1 to 25 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 25 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 25 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 25 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 25 carbon atoms, a substituted or unsubstituted aryl group having 6 to 24 carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 30 cyclic atoms, a substituted or unsubstituted aryloxy group having 6 to 24 carbon atoms, a substituted or unsubstituted alkylthio group having 1 to 25 carbon atoms, a substituted or unsubsituted arylthio group having 6 to 24 carbon atoms, alkyl or aryl substituted silyl group, alkyl or aryl substituted carbonyl group, a substituted phosphoryl group or a cyano group,

nc is 0, 1, 2, 3 or 4, when nc is 2, 3 or 4, the plural R^(n62)s may be same or different, and the plural R^(n62)s may be bonded to each other to form a ring structure,

Y^(n3) represents an oxygen atom or a sulfur atom.

The present invention further relates to an organic electroluminescence device, wherein the light emitting layer comprises a heterocyclic derivative represented by the general formula (N-2) and at least one compound of formula (I). The compound of formula (N-2) is in a preferred embodiment used as host material.

wherein,

L^(n1) represents a substituted or unsubstituted aryl group having 6 to 24 carbon atoms, or a substituted or unsubstituted heterocyclic group having 5 to 30 cyclic atoms,

nf is 0, 1, 2, 3 or 4, when f is 2, 3 or 4, the plural L^(n1)s may be same or different each other,

Y^(n1) is carbon atom or nitrogen atom,

Ar^(n1) represents a substituted or unsubstituted aryl group having 6 to 24 carbon atoms which shares a carbon atom of an adjacent nitrogen-containing 5-membered ring and Y^(n1) and is fused to the nitrogen-containing 5-membered ring, or a substituted or unsubstituted heterocyclic group having 5 to 30 cyclic atoms which shares a carbon atom of an adjacent nitrogen-containing 5-membered ring and Y^(n1) and is fused to the nitrogen-containing 5-membered ring,

R^(n50) and R^(n51) each independently represents hydrogen, halogen atom, a substituted or unsubstituted alkyl group having 1 to 25 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 25 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 25 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 25 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 25 carbon atoms, a substituted or unsubstituted aryl group having 6 to 24 carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 30 cyclic atoms, a substituted or unsubstituted aryloxy group having 6 to 24 carbon atoms, a substituted or unsubstituted alkylthio group having 1 to 25 carbon atoms, a substituted or unsubsituted arylthio group having 6 to 24 carbon atoms, alkyl or aryl substituted silyl group, alkyl or aryl substituted carbonyl group, a substituted phosphoryl group or a cyano group, or R⁵⁰ and R⁵¹ may be bonded to each other to form a substituted or unsubstituted aryl group having 6 to 24 carbon atoms;

R^(n60) represents a substituted or unsubstituted fused-aryl group having 10 to 24 carbon atoms or a substituted or unsubstituted fused-heteroaryl group having 9 to 30 cyclic atoms.

Preferred groups R^(n60) are mentioned above.

The compound represented by formula (N-2) is preferably represented by formula (N-2-1).

wherein

R^(n60), L^(n1), nf, Y^(n1) and Ar^(n1) are as defined in formula (N-2),

R^(n52) represents hydrogen, halogen atom, a substituted or unsubstituted alkyl group having 1 to 25 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 25 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 25 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 25 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 25 carbon atoms, a substituted or unsubstituted aryl group having 6 to 24 carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 30 cyclic atoms, a substituted or unsubstituted aryloxy group having 6 to 24 carbon atoms, a substituted or unsubstituted alkylthio group having 1 to 25 carbon atoms, a substituted or unsubsituted arylthio group having 6 to 24 carbon atoms, alkyl or aryl substituted silyl group, alkyl or aryl substituted carbonyl group, a substituted phosphoryl group or a cyano group,

nc is 0, 1, 2, 3 or 4, when c is 2, 3 or 4, the plural R^(n52)s may be same or different each other and adjacent R^(n52)s may be bonded to each other to form a ring structure.

The compound represented by formula (N-2-1) is preferably represented by formula (N-2-2).

wherein R^(n60), L^(n1), nf, R^(n52) and nc are as defined in formula (N-2-1).

The compound represented by formula (N-2-2) is preferably represented by formula (N-2-3).

wherein R^(n60), L^(n1), nf, R^(n52) and nc are as defined in formula (N-2-2),

nd is 0, 1, 2 or 3, when nd is 2 or 3, the plural R^(n52) are same or different each other,

R^(n53) represents a substituted or unsubstituted alkyl group having 1 to 25 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 25 carbon atoms, a substituted or unsubstituted aryl group having 6 to 24 carbon atoms or a substituted or unsubstituted heterocyclic group having 5 to 30 cyclic atoms.

In another embodiment, the compound represented by formula (N-2-1) is preferably represented by formula (N-2-4).

wherein R^(n69), L^(n1), nf, R^(n52) and nc are as defined in formula (N-2-1),

Y^(n2) represents CR^(n54)R^(n55), NR^(n55), oxygen atom or sulfur atom,

R^(n54), R^(n55) and R^(n56) each independently represents a substituted or unsubstituted alkyl group having 1 to 25 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 25 carbon atoms, a substituted or unsubstituted aryl group having 6 to 24 carbon atoms or a substituted or unsubstituted heterocyclic group having 5 to 30 cyclic atoms,

Ar^(n2) represents a substituted or unsubstituted aryl group having 6 to 24 carbon atoms which shares carbon atoms of two adjacent nitrogen-containing 5-membered rings and is fused to the two nitrogen-containing 5-membered rings, or a substituted or unsubstituted heterocyclic group having 5 to 30 cyclic atoms which shares carbon atoms of two adjacent nitrogen-containing 5-membered rings and is fused to the two nitrogen-containing 5-membered rings.

Y^(n2) in formula (N-2-4) preferably represents CR^(n54)R^(n55) _(or) NR^(n56) (R^(n54) to R^(n56) are as defined in formula (N-2-4)).

In another embodiment, the compound represented by formula (N-2-1) can be represented by formula (N-2-7).

wherein R^(n69), X^(n1) to X^(n3), R^(n5), R^(n6), L^(n1), nf, R^(n52) and nc are as defined in formula (N-2-1).

Preferred groups R^(n60) are mentioned above.

Particularly preferred groups R^(n60) are mono-valent residues represented by formula (a1-2).

wherein R^(n29) to R^(n36) each independently represents hydrogen atom or substituent R^(b),

when plural R^(b)s exist, the plural R^(b)s may be same or different each other, and the plural R^(b)s may be bonded to each other to form a ring structure,

R^(b) represents hydrogen, a substituted or unsubstituted alkyl group having 1 to 25 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 25 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 25 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 25 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 25 carbon atoms, a substituted or unsubstituted aryl group having 6 to 24 carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 30 cyclic atoms, a substituted or unsubstituted aryloxy group having 6 to 24 carbon atoms, a substituted or unsubstituted alkylthio group having 1 to 25 carbon atoms, a substituted or unsubsituted arylthio group having 6 to 24 carbon atoms, alkyl or aryl substituted silyl group, alkyl or aryl substituted carbonyl group, a substituted phosphoryl group or a cyano group.

Preferable examples of the compound represented by formula (a1-2) are as follows.

Among the above examples, a fused-aryl ring containing 4 or more rings, such as fluoranthenyl group is preferable.

Examples for preferred compounds N-2 are therefore compounds of the following formula:

According to another embodiment, the light-emitting layer comprises at least one emitter material and at least two matrix materials, wherein one of the matrix materials is a material selected from before mentioned known host materials and the other matrix material(s) is/are used as co-host(s). Suitable other host material(s) is/are selected from before mentioned general host materials.

In said embodiment, the light-emitting layer is formed from 0.1 to 70% by weight, preferably 1 to 30% by weight, of the at least one emitter material and 30 to 99.9% by weight, preferably 70 to 99% by weight, of a first host and the further matrix material, where the sum total of the at least one emitter material, the further matrix materials adds up to 100% by weight.

The content ratio of the compound of the first host material and the second matrix material as co-host in the light emitting layer is not particularly limited and may be selected accordingly, and the ratio of first host material: second host material is preferably 1:99 to 99:1, more preferably 10:90 to 90:10, each based on mass.

A phosphorescent dopant (phosphorescent emitting material) that forms the emitting layer is a compound that can emit light from triplet excited state. The phosphorescent dopant is not limited as long as it can emit from triplet excited state. The phosphorescent dopant is preferably an organic metal complex containing at least one metal selected from Ir, Pt, Os, Au, Cu, Re and Ru and a ligand. It is preferred that the ligand have an ortho-metalated bond. In respect of a high phosphorescent quantum yield and capability of improving external quantum yield of an emitting device, the phosphorescent dopant is preferably a compound having a metal atom selected from Ir, Os and Pt. Further preferable are a metal complex such as an iridium complex, an osmium complex and a platinum complex, with an ortho-metalated complex being more preferable. Among them, an iridium complex and a platinum complex are more preferable, and an ortho-metalated iridium complex is particularly preferable.

The phosphorescent host is a compound having a function of allowing a phosphorescent dopant to emit light efficiently by efficiently confining the triplet energy of the phosphorescent dopant in the emitting layer. The material for an organic EL device according to the invention is preferable as the phosphorescent host. The emitting layer may comprise one kind of the material for an organic EL device according to the invention or may comprise two or more kinds of the material for an organic EL device according to the invention.

When the material for an organic EL device according to the invention is used as a host material of the emitting layer, the emission wavelength of the phosphorescent dopant contained in the emitting layer is not particularly restricted. It is preferred that at least one kind of the phosphorescent dopant materials contained in the emitting layer have a peak of an emission wavelength of 490 nm or more and 700 nm or less, more preferably 490 nm or more and 650 nm or less. As for the emission color of the emitting layer, red, yellow and green are preferable, for example. By using the compound according to the invention as the host material and by forming an emitting layer by doping the phosphorescent dopant having such an emission wavelength, it is possible to obtain a long-lived organic EL device.

In the organic EL device according to the invention, other compounds than the material for an organic EL device according to the invention can appropriately be selected as the phosphorescent host according to the above-mentioned purpose.

The material for an organic EL device according to the invention and other compounds may be used in combination as the phosphorescent host material in the same emitting layer. When plural emitting layers are present, as the phosphorescent host material for one of these emitting layers, the material for an organic EL device according to the invention is used, and as the phosphorescent host material for one of other emitting layers, other compounds than the material for an organic EL device according to the invention may be used. The material for an organic EL device according to the invention can be used in an organic layer other than the emitting layer. In that case, as the phosphorescent host of the emitting layer, other compounds than the material for an organic EL device according to the invention may be used.

The content of the emitter materials (dopants), preferably the phosphorescent emitter materials, in the light emitting layer is not particularly limited and selected according to the use of the device, and preferably 0.1 to 70% by mass, and more preferably 1 to 30% by mass. If being 0.1% by mass or more, the amount of light emission is sufficient. If being 70% by mass or less, the concentration quenching can be avoided. The further component in the emitting layer is usually one or more host material, which is preferably present in an amount of 30 to 99.9% by mass, more preferably 70 to 99% by mass, wherein the sum of the emitter material(s) and the host material(s) is 100% by mass.

Suitable metal complexes (dopants, especially phosphorescent dopants) for use in the inventive OLEDs, preferably as emitter material, are described as following general formula (E-1).

Wherein M₁ is a metal having an atomic weight greater than 40, preferably, Ir, Pt, Pd, Rh, Re, Ru, Os, TI, Pb, Bi, In, Sn, Sb, Te, Au, or Ag, more preferably Ir, Pt, or Os, most preferably Ir, A₁ represents aryl group having 6 to 24 carbon atoms or heterocyclic group having 3 to 24 cyclic atoms, preferably above mentioned substituents which may have additional substituents,

A2 represents nitrogen containing heterocyclic group having 3 to 24 cyclic atoms, preferably above mentioned substituents which may have additional substituents,

Z₁ represents C or N, preferably N,

(X-Y) is an ancillary ligand, preferably acetylacetonate derivatives, picolinate derivatives, more preferably acetylacetonate derivatives,

m is a value from 1 to the maximum number of ligands that may be attached to the metal; and

m+n is the maximum number of ligands that may be attached to the metal.

If m or n is more than 2, two or more ligands may be the same or different in each occurrence.

According to one embodiment, a metal complex represented by the following general formula (E-2) is more preferable especially for green and yellow emitter,

Wherein M₂ is a metal having an atomic weight greater than 40, preferably, Ir, Pt, Pd, Rh, Re, Ru, Os, TI, Pb, Bi, In, Sn, Sb, Te, Au, or Ag, more preferably Ir, Pt, or Os, most preferably Ir, A₃, A₅ each independently represents aryl group having 6 to 24 carbon atoms or heterocyclic group having 3 to 24 cyclic atoms, preferably above mentioned substituents which may have additional substituents,

A₄, A₆ each independently represents nitrogen containing heterocyclic group having 3 to 24 cyclic atoms, preferably above mentioned substituents which may have additional substituents,

Z₂, Z₃ each independently represents C or N, preferably N,

o is a value from 1 to the maximum number of ligands that may be attached to the metal; and o+p is the maximum number of ligands that may be attached to the metal.

If o or p is more than 2, two or more ligands may be the same or different in each occurrence.

A metal complex represented by the following general formula (T) or (β) is more preferable.

M represents the above mentioned metal atom,

B, C each independently represents aryl group having 6 to 24 carbon atoms or heteroaryl group having 3 to 24 cyclic atoms, preferably phenyl group, dibenzofuran group, dibenzothiophene group, aza-dibenzofuran group, aza-dibenzothiophene group, which may have additional substituents,

A represents a nitrogen containing 6 membered ring structure which may have additional substituents, preferably pyridine, pyrimidine, more preferably pyridine,

X⁴-X⁸ each represents C or N, preferably C,

m represents oxidation state of the metal M, n is 1 or greater than 1,

L′ represents following chemical structure,

wherein A represents nitrogen containing 6 membered ring structure which may have additional substituents, preferably pyridine, pyrimidine, more preferably pyridine,

B represents aryl group having 6 to 24 carbon atoms or heteroaryl group having 3 to 24 cyclic atoms, preferably phenyl group, dibenzofuran group, dibenzothiophene group, aza-dibenzofuran group, aza-dibenzothiophene group, which may have additional substituents,

X⁹ represents C or N, preferably, N.

Ra, Rb, Rc or Rd each independntly represents hydrogen, a substituted or unsubstituted alkyl group having 1 to 25 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 25 carbon atoms, a substituted or unsubstituted amino group, a substituted or unsubstituted alkenyl group having 2 to 25 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 25 carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 24 carbon atoms, a substituted or unsubstituted aryl group having 6 to 24 carbon atoms or a substituted or unsubstituted heterocyclic group having 5 to 30 cyclic atoms,

Wherein X represents NR, oxygen atom, sulfur atom, BR or Selenium atom,

R represents hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 25 carbon atoms,

A¹, to A⁸ independently represents CH, CR⁵ or N, preferably CH or CR⁵,

R¹ to R⁵ each independently represents a substituted or unsubstituted alkyl group having 1 to 25 carbon atoms, a substituted or unsubstituted aryl group having 6 to 24 ring carbon atoms,

n is 1, 2 or 3, preferably 1.

In another embodiment, a metal complex represented by any one of the following general formula (V), (X), (Y), (Z) can be used.

Wherein R⁵° to R⁵² each represents a substituted or unsubstituted alkyl group having 1 to 25 carbon atoms, a substituted or unsubstituted aryl group having 6 to 24 ring carbon atoms,

k is 0, 1, 2, 3 or 4, m is 0, 1 or 2, I is 0, 1, 2, 3 or 4,

M represents iridium atom (Ir), osmium atom (Os) or platinum atom (Pt).

Formula (V) is preferably represented by formula (V-1). Formula (X) is preferably represented by formula (X-1) or (X-2).

Wherein R⁵⁰, M and k are as defined in formula (V) and (X).

(2) Fluorescent Emitting Layer

The fluorescent emitting layer usually comprises at least one emitter material and at least one host material.

A host material for fluorescent emitting layer is usually selected from general host materials, which preferably have wider band-gap than the emitter material to get highly efficient light emission from the emitter through energy transfer mechanism from the excited host to the emitter. Specific examples of the preferable fluorescent host are, substituted or unsubstituted above mentioned heterocyclic compound; or substituted or unsubstituted aromatic hydrocarbon compound, such as oligo-phenylene derivatives, naphthalene derivatives, fluorene derivatives, fluoranthene derivatives, anthracene derivatives, phenanthrene derivatives, pyrene derivatives, triphenylene derivatives, benzanthracene derivatives, chrysene derivatives, benzphenanthrene derivatives, naphthacene derivstives, benzochrysene derivatives, and so on, preferably anthracene derivatives, pyrene derivatives and naphthacene derivatives, more preferably, anthracene derivatives represented by following general formula (X) especially for fluorescent blue or green device.

Ar_(x1) and Ar_(x2) are independently a substituted or unsubstituted aryl group including 6 to 50 ring carbon atoms, preferably phenyl group, biphenyl group, naphthyl group, phenanthryl group, fluorenyl group, fluoranthenyl group, anthryl group, pyrenyl group, benzphenanthryl group, triphenylenyl group, benzanthryl group, benzochrysenyl group, or a heterocyclic group including 5 to 50 ring atoms, preferably, benzofuranyl group, benzothiophenyl group, indolyl group, dibenzothiophenyl group, dibenzofuranyl group, carbazolyl group, benzocarbazoryl group, dibenzocarbazoryl group, indolophenanthryl group, naphthobenzofuranyl group, naphthobenzothiophenyl group, dinaphthofuranyl group, dinaphthothiophenyl group, benzophenanthlofuranyl group, benzophenanthlothiophenyl group, benzofurodibenzofuranyl group, benzothiodibenzothiophenyl group, benzofurodibenzotihiophenyl group, benzothiodibenzofuranyl group, more preferably oxygen or sulfer containing heteroaromatics, such as furan or thiophene containing heteroaromatics in one of the part of the heteroaromatics. R_(x1) to Rx8 are independently a hydrogen atom, a substituted or unsubstituted aryl group including 6 to 50 ring carbon atoms, a substituted or unsubstituted heterocyclic group including 5 to 50 ring atoms, an alkyl group including 1 to 50 carbon atoms, a substituted or unsubstituted alkoxy group including 1 to 50 carbon atoms, a substituted or unsubstituted aralkyl group including 7 to 50 carbon atoms, a substituted or unsubstituted aryloxy group including 6 to 50 ring carbon atoms, a substituted or unsubstituted arylthio group including 6 to 50 ring carbon atoms, a substituted or unsubstituted alkoxycarbonyl group including 2 to 50 carbon atoms, a substituted or unsubstituted silyl group, a carboxy group, a halogen atom, a cyano group, a nitro group or a hydroxyl group.

An emitter material for fluorescent emitting layer is usually selected from general emitter materials or fluorescent dyes, which preferably have high absorption co-efficiency and high quantum efficiency to get highly efficient light emission from the emitter. Specific examples of the preferable fluorescent emitter are, aromatic hydrocarbon derivatives, such as oligo-phenylene derivatives, naphthalene derivatives, fluorene derivatives, fluoranthenyl group, fused fluoranthenyl group, anthracene derivatives, phenanthrene derivatives, pyrene derivatives, triphenylene derivatives, benzanthracene derivatives, chrysene derivatives, benzphenanthrene derivatives, naphthacene derivstives, benzochrysene derivatives, and so on; aromatic or heterocyclic amine derivatives represented by following general formula (Y); organic boron derivatives represented by general formula (Z),

Y is a substituted or unsubstituted aromatic hydrocarbon group including 6 to 50 ring carbon atoms, preferably fused aromatic hydrocarbon group, or substituted or unsubstituted heterocyclic group having 5 to 50 cyclic atoms.

Ar_(y1), and Ar_(y2) are independently a substituted or unsubstituted aryl group including 6 to 50 ring carbon atoms or a substituted or unsubstituted heterocyclic ring group including 5 to 50 ring atoms, preferably, oxygen or sulfur containing heterocyclic group.

Specific examples of Y include the above-mentioned fused aryl group. Y is preferably a substituted or unsubstituted anthryl group; a substituted or unsubstituted pyrenyl group; a substituted or unsubstituted chrysenyl group; substituted or unsubstituted fluorenyl group, especially substituted or unsubstituted mono-, di-, or tri-benzofuro-fused fluorene, or substituted or unsubstituted mono-, di-, or tri-benzothio-fused fluorene; substituted or unsubstituted dibenzofuran containing heterocyclic group; substituted or unsubstituted dibenzothiophene containing heterocyclic group.

n is an integer of 1 to 4. It is preferred that n be an integer of 1 to 2.

Electron-Transporting Layer

The electron-transporting layer is an organic layer that is formed between the emitting layer and the cathode and has a function of transporting electrons from the cathode to the emitting layer. When the electron-transporting layer is formed of plural layers, an organic layer that is nearer to the cathode is often defined as the electron-injecting layer. The electron-injecting layer has a function of injecting electrons from the cathode efficiently to the organic layer unit.

According to one embodiment, it is preferred that ET layer further comprising the other one or more layer(s) than electron injection layer to enhance efficiency and lifetime of the device, preferably between an electron injection layer and an emitting layer as a hole blocking layer, a exciton blocking layer or a triplet blocking layer.

A compound of the formula (I) is also preferable as all the use of the electron transporting layer, such as an electron transporting layer, an electron-injecting layer, a hole blocking layer, a exciton blocking layer or a triplet blocking layer.

According to one embodiment, it is preferred that an electron-donating dopant be contained in the interfacial region between the cathode and the emitting unit. Due to such a configuration, the organic EL device can have an increased luminance or a long life. Here, the electron-donating dopant means one having a metal with a work function of 3.8 eV or less. As specific examples thereof, at least one selected from an alkali metal, an alkali metal complex, an alkali metal compound, an alkaline earth metal, an alkaline earth metal complex, an alkaline earth metal compound, a rare earth metal, a rare earth metal complex and a rare earth metal compound or the like can be mentioned.

As the alkali metal, Na (work function: 2.36 eV), K (work function: 2.28 eV), Rb (work function: 2.16 eV), Cs (work function: 1.95 eV) and the like can be given. One having a work function of 2.9 eV or less is particularly preferable. Among them, K, Rb and Cs are preferable. Rb or Cs is further preferable. Cs is most preferable. As the alkaline earth metal, Ca (work function: 2.9 eV), Sr (work function: 2.0 eV to 2.5 eV), Ba (work function: 2.52 eV) and the like can be given. One having a work function of 2.9 eV or less is particularly preferable. As the rare-earth metal, Sc, Y, Ce, Tb, Yb and the like can be given. One having a work function of 2.9 eV or less is particularly preferable.

Examples of the alkali metal compound include an alkali oxide such as Li₂O, Cs₂O, or K₂O, and an alkali halide such as LiF, NaF, CsF and KF. Among them, LiF, Li₂O and NaF are preferable. Examples of the alkaline earth metal compound include BaO, SrO, CaO, and mixtures thereof such as Ba_(x)Sr_(1-x)O(0<x<1) and Ba_(x)Ca_(1-x)O (0<x<1). Among them, BaO, SrO and CaO are preferable. Examples of the rare earth metal compound include YbF₃, ScF₃, ScO₃, Y₂O₃, Ce₂O₃, GdF₃ and TbF₃. Among these, YbF₃, ScF₃ and TbF₃ are preferable.

The alkali metal complexes, the alkaline earth metal complexes and the rare earth metal complexes are not particularly limited as long as they contain, as a metal ion, at least one of alkali metal ions, alkaline earth metal ions, and rare earth metal ions. Meanwhile, preferred examples of the ligand include, but are not limited to, quinolinol, benzoquinolinol, acridinol, phenanthridinol, hydroxyphenyloxazole, hydroxyphenylthiazole, hydroxydiaryloxadiazole, hydroxydiarylthiadiazole, hydroxyphenylpyridine, hydroxyphenylbenzimidazole, hydroxybenzotriazole, hydroxyfluborane, bipyridyl, phenanthroline, phthalocyanine, porphyrin, cyclopentadiene, β-diketones, azomethines, and derivatives thereof.

Regarding the addition form of the electron-donating dopant, it is preferred that the electron-donating dopant be formed in a shape of a layer or an island in the interfacial region. A preferred method for the formation is a method in which an organic compound (a light emitting material or an electron-injecting material) for forming the interfacial region is deposited simultaneously with deposition of the electron-donating dopant by a resistant heating deposition method, thereby dispersing the electron-donating dopant in the organic compound. The dispersion concentration of the organic compound: the electron-donating dopant (molar ratio) is 100:1 to 1:100, preferably 5:1 to 1:5.

In a case where the electron-donating dopant is formed into the shape of a layer, the light-emitting material or electron-injecting material which serves as an organic layer in the interface is formed into the shape of a layer. After that, a reductive dopant is solely deposited by the resistant heating deposition method to form a layer preferably having a thickness of from 0.1 nm to 15 nm. In a case where the electron-donating dopant is formed into the shape of an island, the emitting material or the electron-injecting material which serves as an organic layer in the interface is formed into the shape of an island. After that, the electron-donating dopant is solely deposited by the resistant heating deposition method to form an island preferably having a thickness of from 0.05 nm to 1 nm.

The ratio of the main component and the electron-donating dopant in the organic EL device according to the invention is main component: electron-donating dopant =5:1 to 1:5 in terms of molar ratio, more preferably 2:1 to 1:2.

As the electron-transporting material used in the electron-transporting layer other than a compound of the formula (I), an aromatic heterocyclic compound having one or more hetero atoms in the molecule may preferably be used. In particular, a nitrogen containing heterocyclic derivative is preferable.

According to one embodiment, it is preferable that ET layer comprises a nitrogen containing heterocyclics metal chelate, such as 8-hydroxyquinolinolato aluminum, which is generally called as Alq₃.

According to the other embodiment, it is preferable that ET layer comprising substituted or unsubstituted nitrogen containing heterocyclic derivative.

Specific examples of the preferable heterocyclic derivative for ET layer are, 6-membered azine derivatives; such as pyridine derivatives, pyrimidine derivatives, triazine derivatives, pyrazine derivatives, preferably pyrimidine derivatives or triazine derivatives; 6-membered fused azine derivatives, such as quinolone derivatives, isoquinoline derivatives, quinoxaline derivatives, quinazoline derivatives, phenanthroline derivatives, benzoquinoline derivatives, benzoisoquinoline derivatives, dibenzoquinoxaline derivatives, preferably quinolone derivatives, isoquinoline derivatives, phenanthroline derivatives; 5-membered heterocyclic derivatives, such as imidazole derivatives, oxazole derivatives, oxadiazole derivatives, triazole derivatives, thiazole derivatives, thiadiazole derivatives; fused imidazole derivatives, such as benzimidazole derivatives, imidazopyridine derivatives, naphthoimidazole derivatives, benzimidazophenanthridine derivatives, benzimidzobenzimidazole derivatives, preferably benzimidazole derivatives, imidazopyridine derivatives or benzimidazophenanthridine derivatives.

According to the other embodiment, it is preferable ET layer comprises phosphine oxide derivative represented as Ar_(p1)Ar_(p2)Ar_(p3)P=O.

Ar_(p1)˜Ar_(p3) are the substituents of phosphor atom and each independently represent substituted or unsubstituted above mentioned aryl group or substituted or unsubstituted above mentioned heterocyclic group.

According to the other embodiment, it is preferable that ET layer comprises aromatic hydrocarbon derivatives.

Specific examples of the preferable aromatic hydrocarbon derivatives for ET layer are, oligo-phenylene derivatives, naphthalene derivatives, fluorene derivatives, fluoranthenyl group, anthracene derivatives, phenanthrene derivatives, pyrene derivatives, triphenylene derivatives, benzanthracene derivatives, chrysene derivatives, benzphenanthrene derivatives, naphthacene derivstives, benzochrysene derivatives, and so on, preferably anthracene derivatives, pyrene derivatives and fluoranthene derivatives.

Hole-Transporting Layer

The hole-transporting layer is an organic layer that is formed between the emitting layer and the anode, and has a function of transporting holes from the anode to the emitting layer. If the hole-transporting layer is composed of plural layers, an organic layer that is nearer to the anode may often be defined as the hole-injecting layer. The hole-injecting layer has a function of injecting holes efficiently to the organic layer unit from the anode.

A compound of the formula (I) is also preferable as all the use of the hole transporting layer, such as an hole transporting layer, an hole-injecting layer, a electron blocking layer.

Said hole injection layer is generally used for stabilizing hole injection from anode to hole transporting layer which is generally consist of organic materials.

Organic material having good contact with anode or organic material with p-type doping is preferably used for the hole injection layer.

Acceptor materials, or fused aromatic hydrocarbon materials or fused heterocycles which have high planarity, are preferably used, acceptor materials are more preferably used for the hole injection layer.

Specific examples for acceptor materials other than a compound of the formula (I) are, the quinone derivatives with one or more electron withdrawing groups, such as F₄TCNQ(2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane), 1,2,3-Tris[(cyano)(4-cyano-2,3,5,6-tetrafluorophenyl)methylene]cyclopropane, and so on; hexa-azatriphenylene derivatives with one or more electron withdrawing groups, such as hexa-azatriphenylene-hexanitrile; aromatic hydrocarbon derivatives with one or more electron withdrawing groups; aryl boron derivatives with one or more electron withdrawing groups, and so on.

p-doping is usually consist of one or more p-dopant materials and one or more matrix materials. Matrix materials preferably have shallower HOMO level and p-dopant preferably have deeper LU MO level to enhance the carrier density of the layer. Aryl or heteroaryl amine derivatives are preferably used as the matrix materials. Specific examples for the matrix material are the same as that for hole transporting layer which is explained at the later part. Specific examples for p-dopant other than a compound of the formula (I) are the above mentioned acceptor materials, preferably the quinone derivatives with one or more electron withdrawing groups, such as F₄TCNQ, 1,2,3-Tris[(cyano)(4-cyano-2,3,5,6-tetrafluorophenyl)methylene]cyclopropane. The ratio of the p-type dopant is preferably less than 20% of molar ratio, more preferably less than 10%, such as 1%, 3%, 5% and so on.

Hole transporting layer is generally used for injecting and transporting holes efficiently, and aromatic or heterocyclic amine derivatives are preferably used.

Specific examples for hole transporting layer other than a compound of the formula (I) are represented as general formula (H),

Ar₁-Ar₃ each independently represents substituted or unsubstituted aryl group having 5 to 50 carbon atoms or substituted or unsubstituted heterocyclic group having 5 to 50 cyclic atoms, preferably phenyl group, biphenyl group, terphenyl group, naphthyl group, phenanthryl group, triphenylenyl group, fluorenyl group, spirobifluorenyl group, indenofluorenyl group, carbazolyl group, dibenzofuranyl group, dibenzothiophenyl group, carbazole substituted aryl group, dibenzofuran substituted aryl group or dibenzothiophene substituted aryl group; two or more substituents selected among Ar′-Ar³ may be bonded to each other to form a ring structure, such as carbazole ring structure, acridane ring structure and so on.

According to one embodiment, it is preferable that at least one of Ar₁˜Ar₃ have additional one aryl or heterocyclic amine substituent, more preferably Ar₁ has an additional aryl amino substituent, at the case of that it is preferable that Ar₁ represents substituted or unsubstituted biphenylene group, substituted or unsubstituted fluorenylene group.

A second hole transporting layer is preferably inserted between the first hole transporting layer and the emitting layer to enhance device performance by blocking excess electrons or excitons. Specific examples for second hole transporting layer is the same as the first hole transporting layer. It is preferably that second hole transporting layer have higher triplet energy to block triplet exciton especially for phosphorescent green device, such as the compounds of formula (I), bicarbazole derivatives, biphenylamine derivatives, triphenylenyl amine derivatives, fluorenyl amine detrivatives, carbazole substituted arylamine derivatives, dibenzofuran substituted arylamine derivatives, dibenzothiophene substituted arylamine derivatives, and so on.

The present invention therefore further relates to the organic electroluminescence device according to the present application, wherein a hole transporting layer is provided between the anode and the light emitting layer, and the hole transporting layer comprises at least one compound of formula (I).

Spacing Layer

The spacing layer is a layer provided between the fluorescent emitting layer and the phosphorescent emitting layer when the fluorescent emitting layer and the phosphorescent emitting layer are stacked in order to prevent diffusion of excitons generated in the phosphorescent emitting layer to the fluorescent emitting layer or in order to adjust the carrier balance. Further, the spacing layer can be provided between the plural phosphorescent emitting layers.

Since the spacing layer is provided between the emitting layers, the material for the spacing layer is preferably a material having both electron-transporting properties and hole-transporting properties. In order to prevent diffusion of the triplet energy in adjacent phosphorescent emitting layers, it is preferred that the spacing layer have a triplet energy of 2.6 eV or more. As the material used for the spacing layer, the same material as those used in the above-mentioned hole-transporting layer can be given.

Barrier Layer

It is preferred that the organic EL device according to the invention have a barrier layer such as an electron-barrier layer, a hole-barrier layer and a triplet barrier layer in a part that is adjacent to the emitting layer. Here, the electron-barrier layer is a layer that serves to prevent leakage of electrons from the emitting layer to the hole-transporting layer, and the hole-barrier layer is a layer that serves to prevent leakage of holes from the emitting layer to the electron-transporting layer.

The triplet barrier layer prevents diffusion of triplet excitons generated in the emitting layer to the surrounding layers, and has a function of preventing energy deactivation of triplet excitons on molecules in the electron-transporting layer other than the emitting dopant by confining the triplet excitons within the emitting layer.

When the triplet barrier layer is provided, in the phosphorescent emitting device, the following is considered. The triplet energy of the phosphorescent emitting dopant is taken as ET_(d) and the triplet energy of the compound used as the triplet barrier layer is taken as ET_(TB). If the energy relationship E^(T) _(d) <E^(T) _(TB) is satisfied, in respect of energy, the triplet excitons of the phosphorescent emitting dopant is confined (i.e. the triplet excitons cannot be moved to other molecules), whereby the energy deactivation route other than emission on the dopant is cut off, leading to efficient emission. However, even when the relationship E^(T) _(d) <E^(T) _(TB) is established, if the energy difference ΔE^(T)=E^(T) _(TB)−ET_(d) is small, it is thought that, in an environment at around room temperature where the device is actually driven, due to thermal energy of the surrounding area, the triplet excitons can move to other molecules by endothermically overcoming this energy difference ΔE^(T). In particular, in the case of phosphorescent emission that has a longer exciton life as compared with fluorescent emission, effects of the endothermic move of excitons relatively tend to appear. Relative to the thermal energy at room temperature, a larger energy difference ΔE^(T) is preferable. The energy difference ΔE^(T) is further preferably 0.1 eV or more, and particularly preferably 0.2 eV or more. On the other hand, in a fluorescent device, as the triplet barrier layer of the TTF device configuration disclosed in WO2010/134350A1, the inventive compounds of formula (I) can be used.

The electron mobility of the material constituting the triplet barrier layer is desirably 10⁻⁶ cm²/Vs or more in a field intensity range of 0.04 to 0.5 MV/cm. As the method for measuring the electron mobility of an organic material, several methods that include the Time of Flight method are known. Here, the electron mobility means an electron mobility that is determined by the impedance spectroscopy.

The electron mobility of the electron-injecting layer is desirably 10⁻⁶ cm²/Vs or more in a field intensity range of 0.04 to 0.5 MV/cm. The reason is that, by this electron mobility, injection of electrons from the cathode to the electron-transporting layer is promoted, and as a result, injection of electrons to adjacent barrier layer and emitting layer is promoted, enabling the device to be driven at a lower voltage.

The organic EL device using the inventive compounds of formula (I) can be used as an emitting device in a panel module used in various displays.

The organic EL device using the inventive compounds of formula (I) can be used as a display element of a TV, a mobile phone and a PC; or an electronic apparatus such as lightings or the like.

The OLEDs (organic EL devices) can be used in all apparatus in which electroluminescence is useful. Suitable devices are preferably selected from stationary and mobile visual display units and illumination units. Stationary visual display units are, for example, visual display units of computers, televisions, visual display units in printers, kitchen appliances and advertising panels, illuminations and information panels. Mobile visual display units are, for example, visual display units in cellphones, tablet PCs, laptops, digital cameras, MP3 players, vehicles and destination displays on buses and trains. Further devices in which the inventive OLEDs can be used are, for example, keyboards; items of clothing; furniture; wallpaper. In addition, the present invention relates to a device selected from the group consisting of stationary visual display units such as visual display units of computers, televisions, visual display units in printers, kitchen appliances and advertising panels, illuminations, information panels, and mobile visual display units such as visual display units in cellphones, tablet PCs, laptops, digital cameras, MP3 players, vehicles and destination displays on buses and trains; illumination units; keyboards; items of clothing; furniture; wallpaper, comprising at least one inventive organic light-emitting diode or at least one inventive light-emitting layer.

The following examples are included for illustrative purposes only and do not limit the scope of the claims. Unless otherwise stated, all parts and percentages are by weight.

EXAMPLES I Synthesis Examples Synthesis Example 1: Compound 1 Synthesis Example 1-1

In a nitrogen flushed 1000 ml three-necked round-bottomed flask 4-bromo-2,5-difluoroaniline (20.5 g, 99 mmol) and 2-methoxyphenylboronic acid (17.97 g, 118 mmol) were dissolved in dimethoxyethane (200 ml) under nitrogen. 2M-sodium carbonate solution (99 ml, 197 mmol) and tetrakis(triphenylphosphine)palladium(0) (5.69 g, 4.93 mmol) were added to the reaction mixture. The reaction mixture was heated in an oil bath at 100° C. for 7 hours. Water was added to the reaction mixture followed by extraction with toluene. The combined organic layers were concentrated. The crude product was added to a silica gel column and was eluted with dichloromethane and hexane to give 25 g of white solid (quant, Intermediate 1). The identification of the intermediate 1 was made by FD-MS (field desorption mass spectrometry) analysis.

Synthesis Example 1-2

In a 1000 ml three-necked round-bottomed flask intermediate 1 (19.4 g, 82.4 mmol) was dissolved in acetone. 164 ml Hydrochloric acid (80 ml, 494 mmol) was added to the reaction mixture dropwise. Sodium nitrite (6.8 g, 99 mmol), as a solution in water (16 ml), was added to the reaction mixture dropwise. Potassium iodide (20.5 g, 124 mmol), as a solution in water (80 ml), was added to the reaction mixture dropwise. Water was added to the reaction mixture followed by extraction with toluene and then washed with 5% sodium sulfite solution. The combined organic layers were concentrated. The crude product was added to a silica gel column and was eluted with dichloromethane and hexane to give 14.4 g of white solid (86% yield, intermediate 2). The identification of the intermediate 2 was made by FD-MS (field desorption mass spectrometry) analysis.

Synthesis Example 1-3

In a dried 200 ml three-necked round-bottomed flask intermediate 2 (8.9 g, 25.7 mmol) and (5-chloro-2-methoxyphenyl)boronic acid (5.75 g, 30.9 mmol) were dissolved in dimethoxyethane (52 ml). Tetrakis(triphenylphosphine)palladium(0) (0.594 g, 0.514 mmol) and 2M-sodium carbonate solution (25.7 ml, 51.4 mmol), were added to the reaction mixture. The reaction mixture was heated in an oil bath at 100° C. for 7 hours. Water was added to the reaction mixture followed by extraction with toluene and then washed with water. The combined organic layers were concentrated. The crude product was added to a silica gel column and was eluted with toluene. The crude material was crystallized from ethyl acetate to give 5.3 g of white solid (57% yield, intermediate 3). The identification of the intermediate 3 was made by FD-MS (field desorption mass spectrometry) analysis.

Synthesis Example 1-4

In a nitrogen flushed 100 ml three-necked round-bottomed flask intermediate 3 (4.70 g, 13.03 mmol) was dissolved in dichloromethane under nitrogen. The reaction mixture was cooled to 0° C. with an ice/water bath. 1 M-tribromoborane in dichloromethane (52.1 ml, 52.1 mmol) was added to the reaction mixture dropwise. The reaction mixture was heated to room temperature for 2 hours. The reaction mixture was cooled to 0° C. with an ice/water bath. Ice was added to the reaction mixture. The reaction mixture was filtered through a glass fiber paper and the filter cake was rinsed with water and dried to give 4.1 g of white solid (95% yield, intermediate 4). The identification of the intermediate 4 was made by FD-MS (field desorption mass spectrometry) analysis.

Synthesis Example 1-5

In a dried 200 ml three-necked round-bottomed flask intermediate 4 (2.78 g, 8.36 mmol) and potassium carbonate (3.46 g, 25.1 mmol) were dissolved in N-methyl-2-pyrrolidone (84 ml) under nitrogen. The reaction mixture was heated to 130° C. with an oil bath for 24 hours. The reaction mixture was added to water. The precipitation was rinsed with water and methanol and dried to give 2.0 g of white solid (82% yield, intermediate 5). The identification of the intermediate 5 was made by FD-MS (field desorption mass spectrometry) analysis.

Synthesis Example 1-6

The procedure of the synthesis of intermediate 1 was repeated except for using 3-bromocarbazole in place of 4-bromo-2,5-difluoroaniline and using 9-phenylcarbazole-3-yl boronic acid in place of 2-methoxyphenylboronic acid. The identification of the intermediate 6 was made by FD-MS (field desorption mass spectrometry) analysis.

Synthesis Example 1-7

In a nitrogen flushed 100 ml three-necked round-bottomed flask intermediate 6 (2.04 g, 5 mmol), intermediate 5 (1.61 g, 5.5 mmol), 2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl (0.164 g, 0.4 mmol), tris(dibenzylideneacetone)dipalladium(0) (0.092 g, 0.1 mmol) and sodium tert-butoxide (1.44 g, 15 mmol) were dissolved in xylene under nitrogen. The reaction mixture was heated 140° C. with an oil bath for 22 hours. The reaction mixture was filtered through a Buchner funnel and the filter cake was dissolved in dichloromethan. The crude product was added to a silica gel column and was eluted with dichloromethan and then washed with heated dioxane to give 1.88 g of white solid (57% yield, compound 1). The compound was measured for FD-MS (field desorption mass spectrometry), maximum ultraviolet absorption wavelength (UV(PhMe) λmax) in toluene, and maximum fluorescence wavelength (FL(PhMe, λex=300 nm) λmax) in toluene.

The results are shown below.

FDMS: calcd. for C48H28N202=664, found m/z=664 (M+)

UV(PhMe) λmax: 341 nm

FL(PhMe, λex=300 nm) λmax: 401 nm

Synthesis Example 2: Compound 2 Synthesis Example 2-1

The procedure of the synthesis of intermediate 1 was repeated except for using 1-bromo-2,4-dimethoxybenzene in place of 4-bromo-2,5-difluoroaniline and using 2-fluorophenylboronic acid in place of 2-methoxyphenylboronic acid. The identification of the intermediate 7 was made by FD-MS (field desorption mass spectrometry) analysis.

Synthesis Example 2-2

In a nitrogen flushed 300 ml three-necked round-bottomed flask intermediate 7 (15.0 g, 64.5 mmol) was dissolved in DMF (30 ml) under nitrogen. The reaction mixture was cooled to 0° C. with an ice/water bath. N-bromosuccinimide (11.2 g, 62.9 mmol), as a solution in DMF (30 ml), was added to the reaction mixture dropwise. The reaction mixture was heated to room temperature for 20 hours. Water was added to the reaction mixture followed by extraction with toluene. The combined organic layers were dried sodium sulfate, filtered and concentrated. The crude material was crystallized from acetone and methanol to give 14.8 g of white solid (73% yield). The identification of the intermediate 8 was made by FD-MS (field desorption mass spectrometry) analysis.

Synthesis Example 2-3

In a nitrogen flushed 500 ml three-necked round-bottomed flask intermediate 8 (14.8 g, 47.6 mmol), bis(pinacolato)diboron (24.2 g, 95 mmol), [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II) complex with dichloromethane (1.5 g, 3 mol %) and potassium acetate (14.0 g, 143 mmol) were dissolved in 1,4-dioxane (200 ml) under nitrogen. The reaction mixture was heated to 70° C. with an oil bath for 20 hours. Toluene was added to the reaction mixture followed by vacume concentration. The crude product was added to a silica gel column and was eluted with toluene to give 11.7 g of white solid (66% yield). The identification of the intermediate 9 was made by FD-MS (field desorption mass spectrometry) analysis.

Synthesis Example 2-4

The procedure of the synthesis of intermediate 1 was repeated except for using 4-bromo-1-fluoro-2-iodobenzene in place of 4-bromo-2,5-difluoroaniline and using intermediate 10 in place of 2-methoxyphenylboronic acid. The identification of the intermediate 11 was made by FD-MS (field desorption mass spectrometry) analysis.

Synthesis Example 2-5

The procedure of the synthesis of intermediate 4 was repeated except for using intermediate 11 in place of intermediate 3. The identification of the intermediate 12 was made by FD-MS (field desorption mass spectrometry) analysis.

Synthesis Example 2-6

The procedure of the synthesis of intermediate 5 was repeated except for using intermediate 12 in place of intermediate 4. The identification of the intermediate 13 was made by FD-MS (field desorption mass spectrometry) analysis.

Synthesis Example 2-7

The procedure of the synthesis of compound 1 was repeated except for using intermediate 13 in place of intermediate 5. The compound was measured for FD-MS (field desorption mass spectrometry), maximum ultraviolet absorption wavelength (UV(PhMe) λmax) in toluene, and maximum fluorescence wavelength (FL(PhMe, λex=300 nm) λmax) in toluene. The results are shown below.

FDMS: calcd. for C48H28N202=664, found m/z=664 (M+)

UV(PhMe) λmax: 335 nm

FL(PhMe, λex=300 nm) λmax: 406 nm

Synthesis Example 3: Compound 3 Synthesis Example 3-1

The procedure of the synthesis of intermediate 1 was repeated except for using 2,3-difluoro-1,4-diiodobenzene in place of 4-bromo-2,5-difluoroaniline. The identification of the intermediate 14 was made by FD-MS (field desorption mass spectrometry) analysis.

Synthesis Example 3-2

The procedure of the synthesis of intermediate 8 was repeated except for using intermediate 7 in place of intermediate 8. The identification of the intermediate 15 was made by FD-MS (field desorption mass spectrometry) analysis.

Synthesis Example 3-3

The procedure of the synthesis of intermediate 1 was repeated except for using intermediate 15 in place of 4-bromo-2,5-difluoroaniline. The identification of the intermediate 16 was made by FD-MS (field desorption mass spectrometry) analysis.

Synthesis Example 3-4

The procedure of the synthesis of intermediate 4 was repeated except for using intermediate 16 in place of intermediate 3. The identification of the intermediate 17 was made by FD-MS (field desorption mass spectrometry) analysis.

Synthesis Example 3-5

The procedure of the synthesis of intermediate 5 was repeated except for using intermediate 17 in place of intermediate 4. The identification of the intermediate 18 was made by FD-MS (field desorption mass spectrometry) analysis.

Synthesis Example 3-6

The procedure of the synthesis of compound 1 was repeated except for using intermediate 18 in place of intermediate 5. The compound was measured for FD-MS (field desorption mass spectrometry), maximum ultraviolet absorption wavelength (UV(PhMe) λmax) in toluene, and maximum fluorescence wavelength (FL(PhMe, λex=300 nm) λmax) in toluene. The results are shown below.

FDMS: calcd. for C48H28N202=664, found m/z=664 (M+)

UV(PhMe) λmax: 319 nm

FL(PhMe, λex=300 nm) λmax: 405 nm

Synthesis Example 4: Compound 4 Synthesis Example 4-1

In a nitrogen flushed 300 ml three-necked round-bottomed flask 3-fluorodibenzofuran (5.49 g, 29.5 mmol) was dissolved in tetrahydrofuran (58 ml) under nitrogen. The reaction mixture was cooled to −50° C. with a dry ice/acetone bath. n-Butyllithium solution 1.6 M in hexanes (18.4ml, 29.5 mmol) was added to the reaction mixture. 1,2-Dibromoethane (8.31 g, 44.2 mmol) was added to the reaction mixture. The reaction mixture was heated to room temperature for 5 hours. Water and methanol were added to the reaction mixture followed by extraction with toluene. The reaction mixture was washed with brine. The combined organic layers were dried MgSO₄, filtered and concentrated. The crude product was added to a silica gel column and was eluted with hexane to give 7.1 g of white solid (86% yield). The identification of the intermediate 19 was made by FD-MS (field desorption mass spectrometry) analysis.

Synthesis Example 4-2

The procedure of the synthesis of intermediate 1 was repeated except for using intermediate 19 in place of 4-bromo-2,5-difluoroaniline and using (2-chloro-5-methoxyphenyl)boronic acid in place of 2-methoxyphenylboronic acid. The identification of the intermediate 20 was made by FD-MS (field desorption mass spectrometry) analysis.

Synthesis Example 4-3

The procedure of the synthesis of intermediate 4 was repeated except for using intermediate 20 in place of intermediate 3. The identification of the intermediate 21 was made by FD-MS (field desorption mass spectrometry) analysis.

Synthesis Example 4-4

The procedure of the synthesis of intermediate 5 was repeated except for using intermediate 21 in place of intermediate 4. The identification of the intermediate 22 was made by FD-MS (field desorption mass spectrometry) analysis.

Synthesis Example 4-5

The procedure of the synthesis of compound 1 was repeated except for using intermediate 22 in place of intermediate 5. The compound was measured for FD-MS (field desorption mass spectrometry) and maximum fluorescence wavelength (FL(PhMe, λex=300 nm) λmax) in toluene. The results are shown below.

FDMS: calcd. for C48H28N202=664, found m/z=664 (M+)

FL(PhMe, λex=300 nm) λmax: 405 nm

Synthesis Example 5: Compound 5 Synthesis Example 5-1

The procedure of the synthesis of intermediate 1 was repeated except for using intermediate 19 in place of 4-bromo-2,5-difluoroaniline. The identification of the intermediate 23 was made by FD-MS (field desorption mass spectrometry) analysis.

Synthesis Example 5-2

The procedure of the synthesis of intermediate 4 was repeated except for using intermediate 23 in place of intermediate 3. The identification of the intermediate 24 was made by FD-MS (field desorption mass spectrometry) analysis.

Synthesis Example 5-3

The procedure of the synthesis of intermediate 5 was repeated except for using intermediate 24 in place of intermediate 4. The identification of the intermediate 25 was made by FD-MS (field desorption mass spectrometry) analysis.

Synthesis Example 5-4

The procedure of the synthesis of intermediate 8 was repeated except for using intermediate 25 in place of intermediate 7. The identification of the intermediate 26 was made by FD-MS (field desorption mass spectrometry) analysis.

Synthesis Example 5-5

The procedure of the synthesis of compound 1 was repeated except for using intermediate 26 in place of intermediate 5. The compound was measured for FD-MS (field desorption mass spectrometry) and maximum fluorescence wavelength (FL(PhMe, λex=300 nm) λmax) in toluene. The results are shown below.

FDMS: calcd. for C48H28N202=664, found m/z=664 (M+)

FL(PhMe, λex=300 nm) λmax: 403 nm

Synthesis Example 6: Compound 6 Synthesis Example 6-1

The procedure of the synthesis of intermediate 9 was repeated except for using intermediate 5 in place of intermediate 8. The identification of the intermediate 27 was made by FD-MS (field desorption mass spectrometry) analysis.

Synthesis Example 6-2

In a nitrogen flushed 350 ml three-necked round-bottomed flask intermediate 6 (5.72 g, 14 mmol), 1-bromo-3-fluorobenzene (14.7 g, 84 mmol), potassium phosphate tribasic (8.92 g, 42 mmol) in N-methyl-2-pyrrolidone(NMP) under nitrogen. The reaction mixture was heated 170° C. with an oil bath for 24 hours. The reaction mixture was cooled down and then precipitate salts were filtered. NMP was evaporated from the crude product. Ethanol was added to the crude product, the product precipitated, the product was washed with ethanol and water and dried under vacuum at 80° C. The product crystallized in 1-methoxy-2-proponol to give 5.02 of white solid (64% yield, intermediate 28). The identification of the intermediate 28 was made by FD-MS (field desorption mass spectrometry) analysis.

Synthesis Example 6-3

The procedure of the synthesis of intermediate 1 was repeated except for using intermediate 28 in place of 4-bromo-2,5-difluoroaniline and using intermediate 27 in place of 2-methoxyphenylboronic acid. The compound was measured for FD-MS (field desorption mass spectrometry) and maximum fluorescence wavelength (FL(PhMe, λex=350 nm) λmax) in toluene. The results are shown below.

FDMS: calcd. for C54H32N202=740, found m/z=740 (M+)

FL(PhMe, λex=350 nm) λmax: 405 nm

Synthesis Example 7: Compound 7 Synthesis Example 7-1

The procedure of the synthesis of intermediate 28 was repeated except for using 1-bromo-4-fluorobenzene in place of 1-bromo-3-fluorobenzene. The identification of the intermediate 29 was made by FD-MS (field desorption mass spectrometry) analysis.

Synthesis Example 7-2

The procedure of the synthesis of intermediate 1 was repeated except for using intermediate 29 in place of 4-bromo-2,5-difluoroaniline and using intermediate 27 in place of 2-methoxyphenylboronic acid. The compound was measured for FD-MS (field desorption mass spectrometry) and maximum fluorescence wavelength (FL(PhMe, λex=350 nm) λmax) in toluene. The results are shown below.

FDMS: calcd. for C54H32N202=740, found m/z=740 (M+)

FL(PhMe, λex=350 nm) λmax: 406 nm

II Application Examples Application Example 1

A glass substrate with 120 nm-thick indium-tin-oxide (ITO) transparent electrode (manufactured by Geomatec Co., Ltd.) used as an anode was first cleaned with isopropanol in an ultrasonic bath for 10 min. To eliminate any possible organic residues, the substrate was exposed to an ultraviolet light and ozone for further 30 min. This treatment also improves the hole injection properties of the ITO. The cleaned substrate was mounted on a substrate holder and loaded into a vacuum chamber. Thereafter, the organic materials specified below were applied by vapor deposition to the ITO substrate at a rate of approx. 0.2-1 Å/sec at about 10⁻⁸ -10⁻⁸ mbar. As a hole injection layer, 5 nm-thick of compound HI was applied. Then 100 nm-thick of compound HT1 and 60 nm-thick compound HT2 were applied as hole transporting layer 1 and hole transporting layer 2, respectively. Subsequently, a mixture of 5% by weight of an emitter compound (tris[2-phenylpyridinato-C²,N]iridium(111), 47.5% by weight of a host (compound 1) and 47.5% by weight of compound PH1 were applied to form a 40 nm-thick phosphorescent-emitting layer. On the emitting layer, 30 nm-thick compound ET was applied as an electron transport layer. Finally, 1 nm-thick LiF was deposited as an electron injection layer and 80 nm-thick Al was then deposited as a cathode to complete the device. The device was sealed with a glass lid and a getter in an inert nitrogen atmosphere with less than 1 ppm of water and oxygen. To characterize the OLED, electroluminescence spectra were recorded at various currents and voltages. In addition, the current-voltage characteristic was measured in combination with the luminance to determine luminous efficiency and external quantum efficiency (EQE). Driving voltage (Voltage) is given at a current density of 10 mA/cm². The device results are shown in Table 1.

Application Example 2-4 and Comparative Application Example 1-3

Application Example 1 was repeated except for using each compound shown in Table 1 in place of the host (compound 1). The device results are shown in Table 1.

TABLE 1 Appl. Ex. Host Voltage [V] CIE (x, y) Appl. Ex. 1 Compound 1 4.8 0.31, 0.63 Appl. Ex. 2 Compound 2 4.9 0.31, 0.63 Appl. Ex. 3 Compound 3 4.9 0.31, 0.63 Appl. Ex. 4 Compound 4 4.8 0.31, 0.63 Comp. Appl. Ex. 1 Comparative 5.2 0.31, 0.63 Compound 1 Comp. Appl. Ex. 2 Comparative 5.1 0.31, 0.63 Compound 2 Comp. Appl. Ex. 3 Comparative 5.7 0.31, 0.64 Compound 3

The results shown in Table 1 demonstrate that the voltage is improved in the case that an inventive compound 1, 2, 3 and 4 are used as green hosts together with a co-host Compound PH1 in an OLED.

Application Example 5 and Comparative Application Example 4

Application Example 1 or Comparative Application Example 1 was repeated except for using a host compound PH2 in place of the host (compound PH1). The device results are shown in Table 2.

To characterize the OLED, electroluminescence spectra were recorded at various currents and voltages. In addition, the current-voltage characteristic was measured in combination with the luminance to determine luminous efficiency and external quantum efficiency (EQE). Driving voltage (Voltage) is given at a current density of 10 mA/cm², and 80% lifetime (LT80), the time spent until the initial luminance at 50 mA/cm² is reduced to 80%, is recorded. The device results are shown in Table 2.

TABLE 2 Voltage LT80 Appl. Ex. Host [V] [hrs] CIE (x, y) Appl. Ex. 5 Compound 1 4.7 150 0.31, 0.63 Comp. Appl. Ex. Comparative Compound 5.2  80 0.31, 0.63 4 1

The results shown in Table 2 demonstrate that the lifetime and voltage are improved in the case that an inventive compound 1 is used as a green host together with a co-host Compound PH2 in an OLED.

Application Examples 6, 7 and Comparative Application Example 5

Application Example 5 was repeated except for using each compound shown in Table 3 in place of the host shown in Table 2. The device results are shown in Table 3.

To characterize the OLED, electroluminescence spectra were recorded at various currents and voltages. In addition, the current-voltage characteristic was measured in combination with the luminance to determine luminous efficiency and external quantum efficiency (EQE). 80% lifetime (LT80), the time spent until the initial luminance at 50 mA/cm² is reduced to 80%, is recorded. The device results are shown in Table 3.

TABLE 3 Appl. Ex. Host LT80 [hrs] CIE (x, y) Appl. Ex. 6 Compound 6 140 0.31, 0.63 Appl. Ex. 7 Compound 7 150 0.31, 0.63 Comp. Appl. Ex. 5 Comparative Compound 4 100 0.31, 0.63 

1. A compound of formula (I):

wherein A is

X_(A) and X_(B) each independently represent O or S; r represents 1, 2 or 3; in the case that r is 2 or 3, X_(B) as well as Ar₃ are the same or different in each occurrence; Ar₁, Ar₂ and Ar₃ each independently represent a substituted or unsubstituted aromatic hydrocarbon group having a ring structure formed of 6 to 30 carbon atoms or a substituted or unsubstituted heterocyclic group having a ring structure formed of 5 to 30 atoms, and which is linked to one aromatic hydrocarbon group of Ar₁, Ar₂ respectively Ar₃ via a carbon-carbon bond; L represents a single bond, a substituted or unsubstituted alkylene group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkylene group having a ring structure formed of 3 to 20 carbon atoms, a divalent silyl group having 2 to 20 carbon atoms, a substituted or unsubstituted divalent aromatic hydrocarbon group having a ring structure formed of 6 to 30 carbon atoms or a substituted or unsubstituted divalent heterocyclic group having a ring structure formed of 5 to 30 atoms; m is 1, 2 or 3; in the case that m is 2 or 3, L is the same or different in each occurrence; R¹⁷ is a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms or a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms, an alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having a ring formed of 3 to 20 carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 24 carbon atoms; L₁ is a single bond, a substituted or unsubstituted alkylene group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkylene group having a ring structure formed of 3 to 20 carbon atoms, a divalent silyl group having 2 to 20 carbon atoms, a substituted or unsubstituted divalent aromatic hydrocarbon group having a ring structure formed of 6 to 30 carbon atoms, or a substituted or unsubstituted divalent heterocyclic group having a ring structure formed of 5 to 30 atoms; n is 1, 2 or 3; in the case that n is 2 or 3, L₁ is the same or different in each occurrence; Ar₄, Ar₅, Ar₆ and Ar₇ each independently represent a substituted or unsubstituted aromatic hydrocarbon group having a ring structure formed of 6 to 30 carbon atoms, or a substituted or unsubstituted heterocyclic group having a ring structure formed of 5 to 30 atoms; wherein the dotted line is a bonding site.
 2. The compound according to claim 1, wherein r is
 1. 3. The compound according to claim 1, wherein m is
 1. 4. The compound according to claim 1, wherein the compound of formula (I) has one of the following formulae:

wherein X²¹ to X³⁰ each independently represent CR_(X) or N, R_(X) is in each occurrence independently H, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having a ring formed of 3 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 24 carbon atoms, a silyl group having 3 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having ring structure formed of 6 to 30 carbon atoms or a substituted or unsubstituted heterocyclic group having a ring structure formed of 5 to 30 atoms, or a substituted or unsubstituted alkylthio group having 1 to 20 carbon atoms, or a substituted or unsubstituted arylthio group having 6 to 30 carbon atoms, or a substituted or unsubstituted aryloxy group having 6 to 30 carbon atoms, a cyano group or a halogen atom; wherein, among X²¹ to X³⁰, if two or more atoms are CR_(X), any two of CR_(X)s are optionally bonded each other to form ring structures; wherein one of X²¹ to X³⁰ in each formula (Ia), (Ib), (Ib′), (Ic), (Id), (Ie), (If), (Ig), (Ih), (Ii) and (Ij) represents a bonding site to -(L)_(m)-A via a carbon atom.
 5. The compound according to claim 4, wherein X²¹ to X³⁰ each independently represent CR_(X).
 6. The compound according to claim 1, wherein A is a group of the following formula:

X¹ to X⁸ and Y¹ to Y⁸ each independently represent CR_(Y) or N, R_(Y) is in each occurrence independently a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having a ring formed of 3 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 24 carbon atoms, a silyl group having 3 to 20 carbon atoms, a substituted or unsubstituted hydrocarbon group having ring structure formed of 6 to 30 carbon atoms or a substituted or unsubstituted aromatic heterocyclic group having a ring structure formed of 5 to 30 atoms, or a substituted or unsubstituted alkylthio group having 1 to 20 carbon atoms, or a substituted or unsubstituted arylthio group having 6 to 30 carbon atoms, or a substituted or unsubstituted aryloxy group having 6 to 30 carbon atoms, a cyano group or a halogen atom; wherein, among X¹ to X⁸ and Y¹ to Y⁸, if two or more atoms are CR_(Y), any two of CR_(Y)s are optionally bonded each other to form ring structures wherein one of X⁵, X⁶, X⁷ or X⁸ and one of Y¹, Y², Y³ or Y⁴, are bonded to each other via L₁
 7. The compound according to claim 1, wherein A is selected from the group consisting of the following formulae:


8. The compound according to claim 7, wherein A is selected from the group consisting of the following formulae:


9. The compound according to claim 1, wherein X¹, X², X³, X⁴, X⁵, X⁶, X⁷, X⁸, Y¹, Y², Y³, Y⁴, Y⁵, Y⁶, Y⁷ and Y⁸ is CR_(Y), wherein one of R_(Y) at one of the positions X⁵ to X⁸ and one of R_(Y) at the positions Y¹ to Y⁴ are replaced by the group -(L₁)_(n)-.
 10. A material for an organic electroluminescence device, comprising the compound according to claim
 1. 11. An organic electroluminescence device, comprising: one or more organic thin film layers comprising a light emitting layer between a cathode and an anode, wherein at least one of the one or more organic thin film layers comprises the compound according to claim
 1. 12. The organic electroluminescence device according to claim 11, wherein the light emitting layer comprises the compound according to 9 claim
 1. 13. The organic electroluminescence device according to claim 11, wherein the light emitting layer comprises a phosphorescent material, which is an ortho-metallated complex comprising a metal atom selected from the group consisting of iridium, osmium and platinum.
 14. The organic electroluminescence device according to claim 12, wherein the light emitting layer further comprises a heterocyclic derivative represented by general formula (N-1):

wherein X^(n1) to X^(n3) each independently represents CR^(n4) or N, R^(n1) to R^(n4) each independently represents hydrogen, halogen atom, a substituted or unsubstituted alkyl group having 1 to 25 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 25 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 25 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 25 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 25 carbon atoms, a substituted or unsubstituted aryl group having 6 to 24 carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 30 cyclic atoms, a substituted or unsubstituted aryloxy group having 6 to 24 carbon atoms, a substituted or unsubstituted alkylthio group having 1 to 25 carbon atoms, a substituted or unsubsituted arylthio group having 6 to 24 carbon atoms, alkyl or aryl substituted silyl group, alkyl or aryl substituted carbonyl group, or a substituted phosphoryl group, in the case of at least one of X_(n1) to X^(n3) represent CR^(n4), two or more sub stituents selected among R^(n1)˜R^(n4) are optionally bonded to each other to form a ring structure.
 15. The organic electroluminescence device according to claim 11, wherein a hole transporting layer is provided between the anode and the light emitting layer, and the hole transporting layer comprises the compound. 